An optical alignment method based on color / relative position of guidance light source is designed, landing boat pilot can determine whether is yawing and the degree of yawing through the relative position of the light source with different colors, so as to improve the pricision and safety when entering into well-dock quickly. Guidance light source beam is of 90 ° horizontal and vertical angle of view, and illuminate sea surface farthest to 200m for uniform lighting, with CREE XPE LED, free-form lens is designed by improved grid mapping method to obtain the required rectangular illumination field. The simulation and experimental results show that the designed LED guidance source can meet the illumination requirements of the landing alignment system.