Aiming at the speed of decomposing the space target on each axis of three-axis photoelectric tracking system is better than of two-axis

but the lack of relevant acquisition strategy is studied

and a scanning acquisition method is established. Based on the error sources that cause the field of uncertain（ FoU）

the size and shape of the Fo U and probability distribution type of the target in this field are analyzed. Under the given capture conditions

according to the characteristics of the Fo U

the method of spiral scanning acquisition is used for target acquisition

and the scanning method is assigned to the three axis. The simulation results show that the spiral scanning based on the three-axis photoelectric tracking system can capture the target in a short time and high probability in the circular Fo U which obeys the two-dimensional Gauss distribution.