With the melt grafting method using styrene (St) as co-monomer to maleic anhydride (MAH)，the VERSIFY (V ethylene-propylene copolymer of the content of ethylene is 12%) was grafted. Different graft yield materials, V-g-(MAH-co-St) (g-V) were obtained. Nylon 6 (PA6)/ PP blends were prepared using twin-screw extruder. Using MFR, SEM, IR and mechanical properties testing analysis methods, morphology and mechanical properties of PA6/PP blends were studying on the different graft yield g-V. The results showed with increasing the graft yield, the minimum melt flow rate decreased and the size of the PP dispersed phase became smaller and more uniform. The addition of taller graft yield materials remarkably improved that the anhydride group in g-V reacted with the amine end groups of the PA6, and PP-PA6 copolymers were formed in situ, which effectively improved the compatibility between PP and PA6. The size of PP domains in the PA6 matrix was significantly reduced. Multi-monomer melt grafting can obtain a high rate of graft material. From the MAH: St = 0.5 to the MAH: St = 1, the grafting yield increased significantly. Continuing to improve MAH: St ratio, the magnitude of changes of graft yield of grafting decreases. Different grafting yield of multi-monomer g-V toughened PA6, a high rate of graft effect was good.