The Xixiagou tectonic belt Dyas lake group formation in Santanghu oilfield located in Tuha Basin is fractured reservoir.Serious well leakage frequently took place during the drilling development. In order to solve the problem of serious well leakage in Santanghu oilfield Ma-49 block tight reservoir，the composite gel drilling fluid（CGDF）technique was developed based on the analysis of the reasons of well leakage regulation in Ma-49 block. The compatibility，pumpability，high-temperature resistance and bearing capacity of the CGDF was analyzed，and the effect of the field application was mentioned. The research showed that the compatibility between the CGDF and the reservior was of high performance. The gelling time of the CGDF was 30 min，which indicated that the CGDF had good pumpability. There was not obvious change of CGDF mud invading depth in the casting bed after aged at the temperature of 100℃ for different aging time，so the CGDF system was of high temperature resistance. Moreover，The CGDF was of good pressure resisting and plugging capability，which could form the effective plugging formation in the gap of 1—3 mm in static/dynamic state condition. The CGDF technique solved the serious well leakage in Ma-49 block tight reservoir and optimized the effects of the drilling process. By applying the CGDF technique，94.57% of the average leakage in the same block was reduced，89.51% of the plugging time was shorted，and 37.26% of the drilling cycle was saved.