Based on the plane geometry and stereo geometry theory and the light refraction law, the output laser axial deviation angle of any point light source is calculated in theory after passing through the spherical shell. Considering the electro-optical detection receiving and the firing systems with different wavelength, the error between the laser firing and the target detection is analyzed and the error change law is simulated and calculated. Calculation results show that the optical axis error must be considered when the wavelength is different between the firing and the detection systems. At the same time, the optical axis error should be compensated in the electro-optical system to achieve accurate detection and target tracking.