In order to investigate the performance of LDPE and EVA， 14 kinds of composite modified asphalt were prepared by 0%，2%，4% LDPE and EVA with 0%，2%，4%，6%，8%，respectively. Rheological test，segregation test and Fourier transform infrared spectroscopy（FTIR）test were applied for their high and low temperature performance and storage stability. The results show that the rutting factor and failure temperature of composite modified asphalt are higher than that of base asphalt. When EVA content is higher than 4%， the high temperature index of the composite modified asphalt is higher than that of SBS modified asphalt. LDPE and EVA can greatly improve the high temperature performance of asphalt. The addition of two kinds of polymers has no obvious effect on the low temperature performance of asphalt. The addition of EVA can improve the storage stability of composite modified asphalt to a certain extent. Infrared spectrum test results show that there is no obvious chemical reaction between LDPE，EVA and asphalt.