Abstract: The nonlinear regression analysis was done for the rheological property of melt in diamond/copper-based powders injection molding to obtain the Cross-WLF model parameters. The influence of melt temperature on filling rate was simulated using Moldflow, a finite element simulation software, and was verified by experiment. The results show that the filling rate increased with temperature increasing, but the increasing rate gradually declined. The filling rate reached 100% when injection pressure was 12 MPa, injection flow rate was 10 cm3·s-1 and injection temperature was 170 ℃. The simulated results fitted well with experimental results. And the molded specimen had no obvious cracks with uniform microstructure, giving the best injection effect under the above conditions.