A temporal-spatial fusion guidance system based on multiple sub-beam interference is proposed. The spatialwatermark pattern is combined with the temporal coded signal to produce a new temporal-spatial watermark coded signal. In the multiple sub-beam interference emission system, the laser is divided into several equal power sub-beams which can produce an effective spatial watermarking interference pattern due to their coherence. Calculation results show that the interference pattern appear special distribution features of alternating brightness and darkness. The operating range and the identification of the guidance system are improved by the watermark encoding mode. When the position offset and angle deviation of the beam splitter, which used in multiple sub-beams coherent emission system, are less than 0.1 λ(λ is the wavelength) and 0.1θ0(θ0 is the beam divergence), respectively, the effect of mechanical vibration on the emission system can be ignored.