Due to the scattering and absorption effect in the cross media wireless optical communication,irradiance scintillation and beam wander are produced,which lead to degradation of laser beam propagation and result in random interference in the transmitted data. To reduce the probability of information loss and realize fast frame synchronization,a method of encoding and decoding for timeslot hopping pulse position modulation(PPM) is proposed. By studying the techniques of encoding,decoding,information framing and transmission for the timeslot hopping PPM,a system implementation scheme is discussed. Experiments have shown that using the frame with one byte data,which was previously modulated by timeslot hopping PPM,to transmit information can further improve the anti interference ability of wireless optical signal transmission. And thus,the timeslot hopping communication protocol agreed by the transmitter and receiver,including timeslot combination and frame synchronization,is useful to reduce interception and crack probability of the information in the transmission and thus achieve fast and reliable communication.