Abstract: The functional monomer of pour depressant polymer used for high wax crude oil is designed by molecular simulation. In view of the pour depressant polymer functional monomer screening, the microstructure and morphology of wax crystal is simulated by the molecular simulation. The effects of different kinds of pour depressant polymer with the wax crystal surface are studied in this paper. The terpolymer poly (styrene-AMPS-octadecyl methyl-acrylate) (PSAS) is synthesized by the method of dispersion copolymerization. The experiments results show that the PVAS have better depression effect (13 ℃) on the simulated oil and real crude oil than commercial EVA (8 ℃). The experimental results also show that PSAS and crude oil have stronger effect, and the indoor results agree with the simulation results.