Using the vision subsystem of global vision artificial fish as research object, to detect and track target(polo)accurately,an target recognition approach based on Artificial Fish Swarm Algorithm (AFSA) with adaptive step size for biomimetic robotic fish is proposed. Firstly, initialize the number of artificial fish, and randomly distributed in pixel matrix which using gradient values of image pixels as objective function. Then calculate the food concentration of every artificial fish’s current position, and choose the minimum as bulletin board value which is assignment to this fish. On this basis, by evaluating the rear-end and cluster behavior, select the optimum for the actual behavior. Update the bulletin board value until find the optimal results. The simulation experiments show that this method can simplify the complexity of calculation and improve system real-time performance. So it is feasible to be used in target detection and tracking of global vision artificial fish.