The interference encoding method of semi-active homing laser-guided system based on multiple sub-beams interference was proposed. The spatial interference pattern was combined with the temporal coded signal to produce a new temporal-spatial coded signal. A coherent emission system of multiple sub-beams was designed, the laser was divided into several equal power sub-beams which could produce an effective spatial interference pattern due to their coherence. Calculation results show that the interference pattern presents special distribution features of alternating brightness and darkness. When the value of (the ratio of diagonal) is between 2.5 to 3.5, the interference pattern is most obvious and pure. When the position offset and angle deviation of the beam splitter are less than 0.1?姿(?姿 is the wavelength) and 0.1?兹0(?兹0 is the beam divergence angle) in the sub-beams coherent emission system, respectively, the effect of mechanical vibration on the interference emission system could be ignored.