The invention discloses a differential multi-pulse position modulation method, and relates to the technical field of the laser communication. The method comprises the following steps: S1, receiving data into a coder circuit, and subdividing the data into an ordered sequence of groups of N binary data; S2, modulating each group of N binary data to an information frame, wherein the information framecontains m time slots, and the m time slots comprise p optical pulses, S3, completely deleting all empty time slots after the last optical pulse in the information frame; S4, taking the next time slot after the last optical pulse as an initial bit of the next information frame; and S5, sending the data according to the modulated signal sequence. A symbol structure can be simplified by the DMPPM modulation on the basis of the MPPM modulation, thereby further improving the bandwidth availability ratio of the system. Since a differential formula is adopted in the DMPPM modulation scheme, the frame synchronization process is omitted, and the complexity of the system can be effectively reduced.