To reduce the error in a beam quality measurement system， which is caused by the output crosstalk of array fibers， a correction method combining hardware design and algorithm construction is proposed， and related principal research and method verification are conducted. First， the crosstalk effect of the array fibers is analyzed based on beam quality measurement requirements and the fiber transmission principle. Second， the principle of crosstalk correction is verified by combining the Lambertian scattering principle and experimental results： the Lambertian scattering principle is used to reduce the divergence angle difference of the output light of fibers， establishing a unified diffuse model to correct spot crosstalk， and the deconvolution algorithm is then used to restore the target spot. Third， the principle of a targeted deconvolution algorithm is introduced， and the design of the relevant algorithm parameters is discussed. Finally， a comparison and analysis of the real spot， the uncorrected spot， and the corrected spot output produced by the fiber are conducted， and the experiment is found to verify the feasibility and effectiveness of the correction method. The experimental results reveal that compared to the uncorrected spot， the relative root mean square error of the intensity distribution of the corrected spot is reduced from 36.06% to 4.67%， and the relative root mean square error of the power in the bucket is reduced from 7.79% to 0.73%. The relative error of the beam width where the power in the bucket is 86.5% is reduced from 10.83% to 3.46%. The total time of image processing and parameter calculation using correction algorithm is about 8 s.