Based on the problem of out-of-codes about the height, height-to-width ratio, layout irregularity and vertical irregularity of the highrise buildings form, the multilevel evaluation model is put forward by applying the fuzzy set theory in this paper. The evaluation level is defined. The objective set of all evaluation level are divided into four subsets. The membership function and weights of different evaluation factors are calculated according to the objective set. The degree how out-of-codes highrise building go beyond the codes is evaluated based on the weighted averaging fuzzy synthesis evaluation, and the aseismic performance of out-of-codes highrise building is evaluated considering of the results of aseismic compute. Then the evaluation is tested by the example.