The principle of space-time coding and decoding algorithms are studied, an Alamouti Space-Time Coding (STC) and decoding solution based on Field-Programmable Gate Array (FPGA) is proposed, and the space-time coding and decoding function of a 2 Transmit 2 Receive (2T2R) Multiple-Input Multiple-Output (MIMO) system is implemented. Detailed simulation tests and performance verification have been carried out. The simulation test results show that compared with the traditional 1 Transmit 1 Receive (1T1R) system, the 2T2R MIMO system using space-time coding and decoding improves the receiving sensitivity performance by 6 dB, verifying the correctness and effectiveness of the solution.