Visualization technology of assembly process based on model-driven plays an important role in improving process efficiency. The evaluation, simulation and optimization of assembly design of complex photoelectric products are focused on. Combined with the establishment of product model base and assembly design process knowledge base, the product integrated assembly information model is constructed. Furthermore, a comprehensive evaluation and analysis system of assembly complexity is constructed to optimize the assembly process based on soft computing method. And the 3D assembly simulation environment based on virtual reality is built to realize the product assembly simulation.