The invention relates to a large-scale MIMO signal detection method based on LLL-SD, which belongs to the technical field of communication testing. The method comprises steps of multiplying an initialchannel matrix by a transformation matrix to obtain a plurality of initial bases, performing LLL reduction on the plurality of initial bases at the same time to generate a plurality of reduction bases with performance differences, and selecting a reduction base with the optimal performance to obtain a channel matrix and a transformation matrix T with good orthogonality and fewer condition numbers, and performing QR decomposition on the channel matrix to obtain an upper triangular matrix and a unitary matrix, multiplying conjugate transpose of the unitary matrix by the received signal vector yto obtain an equalized signal of the received signal, performing serial interference elimination by using characteristics of the upper triangular matrix, and performing decoding by using an SD algorithm of an adaptive sphere radius. According to the method, a plurality of initial bases are used for improving channel conditions, the limitation that a traditional lattice reduction algorithm only starts searching from a single group of bases can be broken through, the algorithm complexity is low, convergence is fast, the error rate of the system is reduced, and reliability is improved.