A finite element model of optical glass aspherical lens is constructed with the nonlinear finite element software MSC.Marc. The general Maxwell model is chosen as the viscoelasticity model and the boundary conditions are set, the heating and pressing processes are simulated, and their temperature and stress are observed and analyzed. The equivalent stress at the touching point is observed, and the result is that it increases when the curvature increases, and decreases when the curvature decreases. Pressing processes at 4 different temperatures are simulated, and their stress and strain effects are compared. The result shows that the equivalent stress decreases when the temperature increases, and the equivalent total strain increases when the temperature increases. 580 ℃ is the optimized temperature. Stresses at 3 different molding velocities are simulated, and the result shows that the equivalent stress increases when the velocity increases. But high temperature or low velocity causes unnecessary waste. 0.1 mm/s is the optimized velocity.