Phase shift shadow moiré profilometry technique has the characteristics of the high definition and automatic measurement, but it requires the calibration for the measurement sensitivity in advance, and the implementation process is complicated. In order to simplify the calibration process, a calibration technique to measure sensitivity in real time based on three frame fringe patterns is proposed. A grating is shifted with vertical grating plane precisely and three frame phase shift fringe patterns are obtained. The fringe pattern background is removed by the subtraction between different frame fringe patterns. A phase shift algorithm based on the matrix norm is developed to extract the introduced phase shift. Rapid calibration of measurement sensitivity is obtained based on the relationship between phase shift and measurement sensitivity. Experiment results show that the proposed method is simple, flexible and can provide a closed-form solution for the calibration of measurement sensitivity. The calibration precision of the proposed method is better than that of the traditional Dirckx method.