The overall scheme of spaceborne laser target indicator is introduced. The targets are tracked by remote sensing imaging subsystem and servo subsystem,and the targets are indicated by laser emission system. The key parameters of remote sensing imaging subsystem are optimized and selected,including operating wavelength,focal length,aperture,integration time and field of view,and then the working wavelength,pulse width,peak power,beam divergence angle and direction accuracy of laser emission system are analyzed. The optical systems of a remote sensing imaging subsystem and a laser reflection subsystem are designed. The results show that the subsystem design can meet the requirements of the spaceborne laser target indicator with 500 km orbital altitude,which can realize laser pointing function for medium-sized ships.