To improve the efficiency of CCD imaging subsidiary system fault diagnosis

the fault tree analysis is adopted to analyse its fault mode

which provides an effective way to find faults in complex system. The importance of FTA is described

the quantitative analysis method of FTA is introduced in detail. Taking CCD imaging subsidiary system of space camera as the research object

on the basis of the forming of fault tree

the establishing of the mean event fault tree and the obtaining of the mean event fault probability

the element hiberarchy fault orientation on CCD imaging subsidiary system of space camera is realized.The analytic results show that using the fault tree guides designer to know clearly the relation and level of components faults in system intuitively

the maintaining efficiency and dependability of system can be improved.