The invention discloses a method for predicting polymer flooding effects under different crude oil viscosity conditions, which comprises the following steps: 1) designing effective viscosities and residual resistance coefficients of different polymer solutions, and carrying out combined design by adopting a uniform design method; 2) simulating oil displacement of different polymer solutions underdifferent crude oil viscosity conditions by adopting commercial simulation software Eclipse; 3) respectively carrying out multiple nonlinear regression processing on the recovery ratio and the maximuminjection pressure difference in the obtained experimental result and the effective viscosity and the residual resistance coefficient to obtain a function relationship between the recovery ratio andthe effective viscosity and a function relationship between the maximum injection pressure difference and the residual resistance coefficient; and 4) predicting the polymer displacement effect under different crude oil viscosity conditions by knowing the crude oil viscosity and the polymer solution performance, and predicting the final recovery ratio and the maximum injection pressure difference.