In this paper, a new peak-to-average power ratio (PAPR) reduction method for spatial modulation(SM) ispresented. By using the matrix with all non-zero elements to precode the signals before transmitting, the transmitpower is scattered over all transmit antennas for achieving the goal of PAPR reduction. If this matrix is also anunitary matrix, the distribution of transmit power over transmit antennas will be uniform and it also could retainthe characteristic of avoiding inter channel interference (ICI) due to the orthogonality of unitary matrix. In caseof a non-ideal amplifier, the proposed method can produce a considerable improvement that increases with anumber of transmit antennas in performance. Furthermore, the new scheme achieves an identical performancewith conventional one in the case of ideal amplifier.