The present invention discloses a MIMO communication system signal detection method applied to a MIMO (Multiple Input Multiple Output) system with m transmitting antennas and n receiving antennas. The method comprises the following steps: acquiring the channel (from m transmitting antennas to n receiving antennas) matrix H by using a channel estimation algorithm; calculating a transmitted signal preliminary estimation vector [{circumflex over (x)}1, {circumflex over (x)}2, . . . , {circumflex over (x)}m]T; dividing said m transmitting antennas into groups; obtaining at least one possible transmitted signal vectors for each group of transmitted signals by using signal detection technique; and finally obtaining possible transmitted signal vectors for all groups of transmitting antennas, combining each group of possible transmitted signal vectors into a m-dimensional possible transmitted signal vector in a logic relationship of tree structure, and forming a set of transmitted signal candidate vectors S from said m-dimensional possible transmitted signal vectors; obtaining a ML solution from said set of transmitted signal candidate vectors S with a ML detection algorithm.