To solve the problems of high autocorrelation sidelobe peakhigh cross-correlation peak, and low convergence rate of the algorithm in the orthogonal polyphase code design for Multiple Input Multiple Output (MIMO) radar, a method based on the Genetic Algorithm (GA) and the Harmony Search (HS) algorithm is proposed for the design of the orthogonal polyphase code of MIMO radar. Each time when the GA has been optimized to a certain extent after iterating several times, the HS algorithm is used to search possible solutions in its neighborhood. This hybrid algorithm possesses the global convergence ability of GA and the neighborhood search ability of the HS algorithm.By adding the HS algorithm, the convergence rates of the autocorrelation sidelobe peak and the cross-correlation peak are faster, and the mainlobe-to-sidelobe ratio is higher.Simulation results show that the proposed method is feasible and effective.