We highlight an automotive powertrain co-simulation solution for developing SiL (Software in loop) simulation environment. This solution provides a co-simulation interface for importing control algorithm from Simulink to Modelica environment using RTW toolbox. Detailed illustration is given on how to realize this co-simulation interface. To verify the co-simulation solution, a SiL environment is constructed for an AMT control software, and a virtual vehicle acceleration experiment is launched in a Modelica simulation environment. This experiment gives reasonable results and validates the co-simulation solution.