Abstract: Through studying the theory of absolute optical encoder, we designed a macro/micro switch measurement . We used the incremental code for low precision measurement ,and the absolute code for high-precision measurement. The incremental acquisition method was used to acquire Moir fringe at a high rate of speed, which could solve the problem of low velocity when using precise absolute optical encoder, and implemented high-speed and high-precision measurement that was a combination of macro and micro. Experiment proves that the precision of high-precision low-speed measurement of absolute position can be up to 0.6 m, the used new-type model of high/low velocity switch measurement can make the comprehensive measurement speed up to 2 m/s.