In order to reduce the use of petroleum asphalt in asphalt mixture, modified plant asphalt was prepared with the plant asphalt as the modifier. The test results of the conventional tests, DSR and BBR were analyzed, so that the best use level of plant asphalt was determined, and the performance of modified plant asphalt mixture and SBS modified asphalt mixture were compared. The results show that compared with the SBS modified asphalt, low temperature crack resistance and fatigue properties of modified plant asphalt enhances, and high temperature performance of modified plant asphalt lowers; the modified plant asphalt has an excellent performance when the content of plant asphalt is 12%(by mass); the Marshall stability, dynamic stability, residual stability, low residual strength ratio and bending strain of modified plant asphalt mixture are 088, 094, 108,111， 115 times than those of ordinary SBS modified asphalt mixture, respectively.