To improve the data transmission efficiency of Gaussian transmission channel, a Gaussian transmission channel optimization algorithm based on Superposition Coding and Multi-user scheduling (MGSC)was proposed. First, the system model of Gaussian transmission channel was proposed, the Probability Density Function (PDF) and the Cumulative Distribution Function (CDF) of distance from the source to the end and the user's average power gain were analyzed. Next, the method of optimal superposition coding and successive interference cancellation was used in Gaussian transmission channel, the optimal power and rate allocation was performed according to each user's utility function, the channel users were selected by the optimal method with probability and then the optimal transmission channel was obtained. Finally, by comparing MGSC with the optimization algorithm of Two-Way Relay Channel wireless signal and power transmission (TWRC), and the data transmission algorithm based on matrix and Lattice Sphere Decoding technique (LSD), the simulation results show that the total data rate of channels for MGSC improves 10.2% and 21.7% and the average effect of channel gain is 5.7% and 6.4% higher when channel access users change. Therefore, the MGSC has better optimization results in the channel transmission rate and the channel gain.