A sphere decoding method applied to a MIMO channel is provided. Multiple constellation points of an nth detection layer corresponding to a MIMO channel matrix are enumerated based on an enumeration rule, and at least one nth sub-set of the nth detection layer is defined. K constellation points are obtained from each of the at least one nth sub-set as preferred points, and Kn preferred points are selected from all the K preferred points of the at least one nth sub-set. K1 preferred points are transferred to a second detection layer from a first detection layer. K(T−1) preferred points are transferred to a Tth detection layer from a (T−1)th detection layer. An optimal solution is determined according to Kn preferred points of the nth detection layer. K and at least one of K1 to KT are determined by the The characteristic of the MIMO channel matrix.