In order to solve the problems of low spectral efficiency and low laser utilization of existing optical spatial pulse position modulation, a layered spatial pulse position amplitude modulation method suitable for atmospheric laser communication is proposed by combining layering technology with spatial pulse position amplitude modulation. In this method, a small number of additional lasers are added to form a multilayer structure, and the pulse position in the pulse position amplitude modulation is used to carry bit information, and the pulse amplitude is used to distinguish different layers. The principle of system layer mapping, spatial pulse position amplitude mapping and its inverse mapping is descripted in detail. Moreover, the bit error rate expression of the proposed scheme is derived. The Monte Carlo simulation method is utilized to further verify its reliability and compare it with the traditional spatial modulation methods. Simulation results show that the proposed scheme can greatly improve the spectral efficiency and reduce the used laser number. For example, at the same transmission bits, the spectral efficiency of (9,4,8,2)- spatial pulse position amplitude modulation scheme is 16 times that of (32,4,128)- spatial pulse position modulation scheme. When bit error rate is 10－3, our proposal improves the signal-to- noise ratio by about 1 dB with employ less than 1/3 number of lasers that used in the (32,4,128)- spatial pulse position modulation scheme. Among them, the parameters in parentheses respectively indicate the number of lasers, the number of detectors, the order of the modulation method, and the number of layers, which are ignored when the number of layers is 1.