A new bi-color 2+1 three-dimensional real-time measurement method is proposed in this paper. The traditional three-dimensional real-time measurement method based on 2+1 algorithm needs to project two frames of phase-shifting grating and one frame of background image. In this method， only two frames of bi-color gratings are needed to be projected. Before measuring， two frames of bi-color gratings are encoded in advance. The red channels of these two bi-color gratings are sinusoidal fringes with a shifting phase of π， and the blue channels are the same background light equivalent to the DC component of these sinusoidal fringes， so the sensitivity ratio of color CMOS camera red to blue channel can be calibrated. During the measurement， two frames of bi-color gratings are encoded with a phase shift difference of π/2 according to the above method and synthesize them into a repetitive video. The repetitive video is projected on the surface of the object to be measured by a projector， and the color deformation fringe image can be collected in real time by using a color CMOS camera. The sequence of color deformed fringe patterns at different moments is extracted by computer processing， so as to realize real-time online 3D measurement of moving objects by using 2+1 algorithm . This method can effectively reduce the color crosstalk by using red and blue channels， and only two frames of bi-color gratings are projected to improve the real-time performance of the measurement. Experimental results and analysis verify the feasibility and effectiveness of the method applied to real-time object motion.