The YBCO composite films doped with Ba₂YTaO₆ (BYTO) single nanoparticles and BYTO/LaAlO₃ (LAO) double nanoparticles were prepared by low-fluorine MOD process. The result showed that the optimum doping amount of BYTO in YBCO film was 6mol%, when the self-field J_c of this film was 1.25 MA/cm ², and the maximum pinning force was 3.02 GN/m ³ at 1.2 T. In the co-doping experiment, BYTO particles with positive lattice mismatch with YBCO and LAO particles with negative lattice mismatch with YBCO were introduced, and the interaction between two particles increased effective doping amount up to 10mol%. With adjustment of the ratio of the two kinds of nanoparticles, it was found that the 6mol% BYTO+4mol% LAO-doped YBCO composite films had a J_c value as high as 0.27 MA/cm ² when the magnetic field was 2 T. This magnetic field in which the maximum pinning force was obtained, increased from 0.42 T for pure YBCO to 1.6 T for codoping, in which the maximum pinning force was 5.6 GN/m ³. The co-doping with positive and negative lattice mismatch nanoparticle effectively improves the superconductivity of YBCO composite film under applied magnetic field.