Premature judgment mechanism of particle swarm is established with fitness function. Adaptive adjustment of particle inertia weigh and acceleration factor of anti cosine strategy are optimized particle swarm to give the apple surface defect process. Simulation results show that improved particle swarm algorithm is more clearer detecting the defect of apple surface, the maximum missing rate test index is 4.5%, and less than other algorithms, and the least time comsuming in complete the missing rate, so that it is the new method for quality detection of apple.