Abstract: Taking the Guizhou Guiding county powder quartz as the filler mineral,influence on mechanical properties of the superfine quartz powder /LDPE composite has been studied.The powder quartz is modified by three kind of surface modification agent.And it is indicate that the mechanical properties of WD-70 modified powder quartz to fill LDPE are best by comparing it with the other,include the active calcium oxide/LDPE composite.Some performances of WD-70 modified powder quartz to fill LDPE are better than LDPE,such as tensile strength,fracture Strength,hardness.The modified powder quartz can make up the strong function of PE.