Abstract: Multi-input multi-output (MIMO) systems can achieve more capacity than single input singleoutput systems. For MIMO systems, maximum likelihood detection is the optimum detection but its exponentialcomplexity limits its application. In this paper, a complex lattice reduction algorithm based on householdertransform is proposed and combined with MIMO suboptimal detection algorithm. Moreover the complexity of thiscomplex lattice reduction algorithm is lower than that of real lattice reduction algorithm. Simulation results showthat MIMO suboptimal detection algorithm based on this complex lattice reduction can approach the optimumperformance of maximum likelihood detection by optimizing channel matrix to get better decision domain.