The application of the laser ranging technology in a certain type of helicopter hub limit actuator angle online dynamic measurement was introduced.The limited actuator angle online testing principle, equipment structure, test methods etc were expounded. Laser ranging technology and servo control technology were used in the hub limit actuator angle online dynamic measurement device,the intellectualized test process was realized . Based on KingView software development platform,the distance that the limit unit opened or closed was measured precisely by high precision laser displacement sensor,then it was input into the computer to calculate,the angle of the limit unit in on/off process was gotten,to determine whether the limit actuator met technical requirements under prescribed speed opened and closed. The angle value was calibrated through high precision angle test equipment , in order to ensure measured data accurate and reliable.The equipment has been applied in many types of the helicopter hub limit actuator test. The test efficiency and accuracy are improved.