We present a coordinate measuring method that has been specially devised to perform measurement of coordinates by projected fringe techniques of projectors in three dimensions. It is composed of two parts:one is a target that moves in three dimensions,and the other is a stationary two-dimensional array of photodetectors. The mini-projector is tied to the target,whose projected fringe is monitored by the photodetectors. Application of a phase-shifting technique allows the phase values of the photodetectors to be precisely measured,which are then fitted to a geometric model of multilateration so as to determine the xyz location of the target by a method of optimization. The measuring principle,iterative method,computer simulation and preliminary results are given. The phase-shifting technique has high accuracy,and strong resistance to noise. Iterative optimization for follow-up provides the basis for the calculation. The experimental results prove that the proposed coordinate measuring method can measure the xyz coordinates of the target with high precision.