The phase measurement method by grating projection is an effective technique in 3 D shape measurement. A novel method-two step phase shifting technique for phase measurement profilometry is proposed. In this method only two phase shifted fringe patterns are necessary in order to extract the phase values, and the phase unwrapping procure is not needed. Hence, this method requires little computing time. The experimental results are given. A comparison, which demonstrates the high accuracy of the new method, is made between the proposed two step and conventional four step phase shifting method.