A technical method of diagnosing rationality of city spatial patterns includes the following steps: 1, constructing an index system comprising a master target layer, a sub-target layer, a factor layer and a divisor layer; 2, after standard data processing, using an analytic hierarchy process and an entropy weight process to determine a weight of the divisor; 3, constructing HL comprehensive diagnosis models for rationality of city developing patterns, the models comprising a scale pattern USR diagnosis model, a spatial pattern UKR diagnosis model and a function pattern UFR diagnosis model; 4, using a fuzzy membership grade function process and a linear weighting summation process to calculate a rationality index for each sub-model; and 5, dividing cities into a highly reasonable city, a relatively reasonable city, an intermediate reasonable city, a lowly reasonable city, and an unreasonable city according to HL comprehensive indexes. The comprehensive diagnosis index system provided by the present invention has universality and comprehensiveness, and has availability and effectiveness when evaluating the data. The completed system evaluating method enables the calculated result of the rationality indexes of the urban developing patterns to be more accurate, and achieves a more scientific evaluation of the urban developing patterns.