In order to solve the problem that it is difficult to separate graphene oxide (GO) from aqueous solution after adsorption of pollutants, PEI-GO composite was prepared by modifying GO with PEI, and the structure and morphology of the composite was characterized by FT-IR, Raman, SEM and EDS. The effects of different adsorption time and adsorbent dosage on the adsorption performance of MB were analyzed, and the kinetic and temperature line models were used to fit them. The separation time of MB adsorbed by GO and PEI-GO was recorded respectively. The results show that PEI-GO composite still has a good two-dimensional nanostructure and the O=C-NH covalent bond which is formed by the reaction of the oxygen-containing functional group in the nano film and the amino group in PEI. The composite PEI-GO has good adsorption property for MB. When the initial concentration of MB is 25mg/L and the input amount of PEI-GO is 30 mg, the adsorption capacity of PEI-GO can reach 204.87mg/g. The adsorption behavior conformed to quasi second-order kinetic model and Freundlich isothermal model. After adsorption, compared with GO adsorption, the separation rate is 4-5 times faster.