The effects of polymer curing agent on vegetation growth and erosion resistance of sandy soil after composite improvement were studied by adding different concentration of curing agent and fibers to a sandy slope. The mechanism of improvement was analyzed by scanning electron microscopy, and the results show that with the increase of curing agent concentration, the germination rate of seeds decreases, and the growth of plants is better when polypropylene fiber is added. The sand slope surface strengthened by macromolecule curing agent and plant has better erosion resistance, and the cohesion and internal friction angle of the soil are obviously enhanced. The polymer curing agent sprayed on the surface of sandy soil forms a certain thickness solidifying layer on the surface of the slope, which makes the reinforced sandy soil have better erosion resistance. The plant stems and leaves on the slope can intercept rainfall, avoid the direct impact of water droplets on the surface of sandy soil. The plant roots play a reinforcing role that can effectively enhance the strength of soil, so that the sandy slope surface strengthened by macromolecule solidifying agent and vegetation has better erosion resistance.