The inverse fringe projection technique using multi\|projectors simultaneously is proposed. Through the absolute phase measurement of the master object, different inverse fringes are generated for the different projectors placed in different directions. During the detection, the projectors project their inverse fringes simultaneously. If the object and master are identical, a standard sine fringe without shadow and break is got on the camera. If the object is deformed, the deformation becomes obvious, and can be evaluated quantificationally by simple Fourier transformation and phase unwrapping. Therefore, the detection of complex and discontinuous objects can be completed with only one fringe image, the problems of shadow and break are solved to a large extent, and consequently the fast online detection of this kind of objects is realized. The principle of this technique is expatiated, and the validity is proved by taking the system of two projectors for example. The analysis of error and requirement of application are also presented.