For the problem of path planning for the autonomous underwater vehicle(AUV), in a 3-D grid map, an algorithm based on the biological inspired model for 3-D path planning and safe obstacle avoidance is proposed. Firstly, based on the establishment of 3-D biological inspired neural network model, the AUV 3-D working environment is represented. There is one-to-one correspondence between each neuron in the neural network and the position of the grid map. Then, the motion path of the AUV is planned on the basis of the distribution of neurons’ active output value in neural network. Finally, the simulation results of path planning in the static and dynamic environment show that biological inspired model can solve effectively the path planning and safe obstacle avoidance for the AUV in the 3-D underwater environment.