Traditional optical spatial modulation has low transmission rate and laser utilization and requires the number of lasers to be an integer power of two. To address these problems, we propose a generalized optical spatial modulation (GOSM) scheme suitable for wireless optical communication, which is combined with pulse position modulation and can simultaneously activate multiple lasers. Aiming at the high complexity of the maximum likehood decoding (ML) algorithm, we propose a signal detection algorithm based on ordered-block minimum mean square error (OB-MMSE). A balance factor is utilized to comprehensively consider the error performance and computational complexity. The proposed OB-MMSE algorithm is improved,and the weight is modified according to the characteristics of the GOSM signal. Moreover, an expression for the threshold selection in the lognormal turbulence channel is derived. Finally, the Monte Carlo simulation is utilized to verify the performance of the proposed solution, and the bit error rate and computational complexity of the proposed OB-MMSE algorithm are compared with those of classical ML and MMSE algorithms. Simulation results demonstrate that the proposed OB-MMSE algorithm can effectively reduce the computational complexity at the expense of a slight bit error rate reduction compared to ML algorithm. Furthermore, the proposed OB-MMSE algorithm can reduce the bit error rate compared to the MMSE algorithm. The proposed solution is applicable to systems with less receivers than transmitters at the cost of a slight increase in the computational complexity.