Port automatic mooring system is a complex system engineering，which involves many subjects such as ship kinematics，structural mechanics，automatic control theory and information technology，and is the product of cross-specialty integration development. The automation of dock mooring is mainly realized through the change of mooring mode，the real-time monitoring of ship posture and movement amount，and the reasonable adjustment of ship and shore interaction force.Based on the advantages of the parallel platform robot in six-free motion simulation，an automatic mooring system for port ships is designed and proposed. The passive damping of each branch of the platform acts as the restoring force to adjust the amount of motion of the mooring ship to realize the active control of ship-shore coordination during the mooring operation. In order to verify the feasibility and effect of the scheme，a functional prototype tank test is carried out.