A new idea for small displacement test and measurement system based on light reflection is presented in this paper. Some theoretical researches using the method and experiments in practice were carried out. The results proved that the theory is feasible and efficient. Compared with the traditional small displacement test and measurement system, such as mechanical displacement magnifier; resistance strain test and measurement method; piezoelectric material strain test and measurement system and so on, this method has the following advantages: it creates little disturbance of the test and measurement system; the displacement magnification coefficient is high and is convenient for user to adjust; the test and measurement precision is high and is very easy for its realization; and the cost is low. It fits a lot of test and measurement situations.