The effect of angular momentum on the competition between fission and particle emission during light system fission process was studied via fission diffusion model. The prescission particle multiplicities were found to increase with decreasing angular momentum. The experimental prescission proton and α particle multiplicities can be fitted for 10.6 MeV/nucleon 84 Kr( 27 Al,binary fission) reaction with this model. Entrance channel effect found in [1] is proved to be angular momentum effect.