This paper proposes a promising detection that applies PSO (particle swarm optimization) as the selection of surviving paths in QRM detection for the coded MIMO system, named as QRM-PSO. Because only a few children nodes's metric are needed to calculate in the PSO search process, QRM-PSO can cut down the complexity further, while keeping the same performance as QRM due to the quasi-random movement of the particles. Simulation results demonstrated that the advantage of QRM-PSO in complexity is obvious especially when antenna number and modulation level are high. The required real multiplication number of QRM-PSO is only 0.4% of that of QRM when transmit antenna number is 20 and 16QAM is employed.