According to the principle of orthogonal test, modified asphalt by waste tire rubber powder（WTR） and reclaimed low density polyethylene（RPE） was prepared by high speed shear mixing method in different processing conditions（shear temperature, shear time and shear rate）. Penetration, softening point and ductility were used as the basis for evaluation to identify the optimal processing condition to produce WTR/RPE modified asphalts and then evaluate the WTR/RPE modified asphalts performance. The test results show that the optimal processing parameters are：shear temperature of 180℃, shear rate of 5000r/min and shear time of 90min. After adding WTR and RPE, the penetration is reduced, while softening point and viscosity of modified asphalt are increased. The recommended content of WTR and RPE should be less than 15% and 4%（by mass）, respectively.