1. A method of symbol detection for a uplink multi-input multi-output (MIMO) CDMA system that adopts dual-signaling at a transmission end to flexibly switch between transmission diversity and spatial multiplexing based on space-time channel conditions, comprising: based on the channel characteristics, data stream of each user can be simultaneously applied with orthogonal space-time block encoding (O-STBC) for transmission diversity and/or spatial multiplexing (V-BLAST) for high spectral efficiency; wherein a successive interference cancellation (SIC) algorithm detects data streams by adopting an algebraic structure of the orthogonal space-time block encoding; and the SIC algorithm can be implemented in block-wise, that the data of an STBC terminal or an antenna of an SM terminal can be detected simultaneously at each iteration; and wherein the symbol detection uses a matched filtered channel matrix with a block orthogonal structure to develop a low complexity recursion-based detector; and during the SIC detection, a weight matrix which is required at each iteration is directly obtained from result of a previous iteration, without additional matrix inversion.