In order to analyze the static factors affecting the urban offensive, the gray analytic hierarchy process is used to evaluate the offensive combat effectiveness of heavy combined battalion. The evaluation index system and evaluation model are established from 3 aspects: intelligence acquisition, equipment performance and command coordination. The weight of each level of evaluation indicators are determined by the analytic hierarchy process. According to the evaluation results, how to improve the overall operational effectiveness of the combat unit is analyzed. The results show that the method can avoid the adverse effects caused by many uncertain factors and human factors, making the evaluation results more reliable and accurate.