Since the concept of sustainable development was put forward in the 1980s, the relationship between cities and sustainability has been widely concerned by countries and regions around the world, our cities are still facing problems such as climate change, population explosion, traffic congestion, environmental deterioration, and increasing social differences, which threaten ecosystem security and human health. Urban form is closely related to these problems. In order to create a healthy living environment, the design of sustainable urban form has become the mainstream of current research. Based on the analysis of relevant researches at home and abroad, this paper systematically summarizes the concept of sustainable urban form and its differences and connections with the concepts of sustainable city, urban form, good urban form and ideal urban form. After a brief review of the current assessment methods of sustainable urban form, it is found that the current assessment methods are not accurate enough. Based on the analysis of the applicability of complex adaptive system to the study of sustainable urban form, the core concepts of complex adaptive system are corresponding to the elements of sustainable urban form. To this end, this paper puts forward five evaluation contents, such as the evaluation of nonlinear feature gap with ideal urban form, the evaluation of spatial mobility of form elements, the evaluation of local and integral form elements, the evaluation of diversity of form elements, and the evaluation of the advantage of form elements identification. A systematic analysis of the evaluation content, using fractal, space syntax, biodiversity, multidimensional index construction and other methods to put forward a specific quantitative framework and steps: using fractal technology to evaluate the nonlinear characteristics of the ideal shape structure, and explain its applicability to the assessment of sustainable urban shape; based on space syntax technology, spatial efficiency concepts based on integration degree and selection degree are used to evaluate the mobility of form elements, and its principle and calculation method are described. The correlation between the global integration degree and the local integration degree of space syntax parameters is used to evaluate the local and global coordination, and the evaluation principle, judgment criteria and methods are described systematically. Three types of sustainable urban morphological diversity are proposed, and the quantitative methods of each type are determined based on the measurement method of biodiversity. At the same time, a quantitative method of the fit degree between diversity and spatial efficiency is proposed to evaluate the spatial effectiveness of diversity. An index system was established to evaluate the advantage of identificationfrom the aspects of adaptability, connectivity and complexity of morphological elements, and the steps of quantifying connectivity and complexity indexes with path network analysis were described in detail.Taking the central urban area of Tianjin as the object to evaluate the sustainable performance of its form, the research finds that: in terms of nonlinear feature gap assessment with the ideal urban form, the current shape dimension of the central urban area has a large gap with the ideal dimension and the fractal dimension of different functional land has obvious changes. In terms of mobility evaluation of form elements, with the increase of spatial scale radius, the spatial efficiency showed a trend of concentric circles, and the spatial efficiency was the highest in the center and gradually decreased to the periphery. In the evaluation of local and overall coordination, the coordination of most streets in the central six districts is good, while the coordination of the peripheral areas of the central urban area is poor. The results also show that the coordination of historical and cultural districts and the overall urban area is perfect. In terms of diversity assessment of form elements, the results show that Santiaoshi, Da Hutong, Quanye Chang, Nanshi and Xinxing streets in the city are poor, other streets are good, and the spatial efficiency and diversity of streets in the old city, the northeast and western edges of the central city and the lower reaches of Haihe River are poor. In terms of morphological factor identification advantages, the path network quantification method is adopted, and the results show that the form elements identification advantages in the old city area are the best, while the first-line streets in the outer ring Road West and North Road in the central city have poor advantages. The field investigation on the evaluation results shows that the evaluation results are in good agreement with the actual morphological performance, which confirms the effectiveness of the evaluation method. It shows that the proposed evaluation method can provide a basis for the design of healthy human settlement environment and has great potential for popularization.