The linear dynamic target(LDT) is designed according to the need of indoor checking and testing for the dynamic characteristic of photoelectric theodolite tracking system,based on the theory of equivalent sine and equivalent target. LDT can offer standard sine optic target and liner optic target which speed is constant. The mathematical model and the max of target′s speed and acceleration is gived. In this paper,LDT′s structure and method of design also is discussed.