Based on DC Ⅰ bio asphalt, the by product of corn processing, blended bio asphalt (BDC Ⅰ) and SBS modified blended bio asphalt (BMDC Ⅰ) were prepared. The pavement performance of the two asphalt mixtures was evaluated, and the improvement measures to the water stability were put forward. First, atomic force microscopy (AFM) was employed to investigate the component compatibility of DC Ⅰ bio asphalt and SBS modifier in the asphalt. Second, according to the different asphalt performance requirements in different pavement layers, the blended bio asphalt BDC Ⅰ and SBS modified blended bio asphalt BMDC Ⅰ were used to prepare AC 25 and AC 20 asphalt mixtures, respectively, and their pavement performances were measured comprehensively. The results show that the presence of bio asphalt increases dynamical stability of the mixture, has little effect on the low temperature performance, but reduces the moisture resistance. Finally, based on the results of the Marshall specimen water immersion 20d test, water solubility is the mainfactor which causes low moisture resistance. Subsequently, three kinds of additives(modifier Ⅰ, Ⅱ, Ⅲ) were chosen to chemically modify the bio asphalt. The water immersion Marshall tests and freeze thaw splitting tests results reveal that the modifier Ⅰ obviously improves the moisture resistance of bio asphalt mixture. The performances of bio asphalt mixture is excellent after modified by additives, and its chemical modification is the focus of future researches.