How to measure conveniently and accurately the motion parameters of the rotor blades of a helicopter is very important to the design and performance analysis of rotor helicopter. According to traditional measurement methods such as strain gauge and grating projection with the defects of cumbersome installation, higher requirements for testing environment and flight performance affected by measurement equipments, a non-contact rotor blade motion parameter measurement method based on 3D digital image is proposed. The method has the advantages of low requirement for testing environment, large quantity measurement parameters and large testing range. Experimental results show that the method is effective for measuring the parameters of the rotors blades.