As a kind of new graphic laser processing method， the femtosecond laser spacing technology， based on the spatiotemporal interference， is more easy， flexible and efficient than traditional ones. However， the imaging distortion introduced by the shrink-beam system has huge influence on the accuracy of processing. This work simulates and analyzes the distortion of the system， and uses the phase hologram of the spatial light modulator to compensate the position change of the spatial light field and uneven light intensity distribution caused by the distortion. The method can make the maximum deviation of the interference pattern near the exposure point approach 0 from 10.66 μm， the relative maximum deviation reduces from 60.42% to under 8% and the two-dimension light intensity distribution get close to flat-top. This algorithm reduces the design requirements of the femtosecond laser space shaping technology of space-time interference for the reduced beam imaging system， and saves cost and time. Based on the above methods， a 1.5 mm×1.5 mm quick response code pattern with multi-level anti-counterfeiting capability was spliced and processed on the stainless steel surface.