Abstract: For improving the mission completion quality，the spacecraft need to adjust their capabilities according to the task and environment reasonably.The ability model of the spacecraft control system，by which the high-level ability value can be described quantitatively，is the theoretical basis for the above adjustment.This paper proposed an ability modeling method through the partial least square structural equation model（PLS-SEM）for the spacecraft control system to achieve quantitative descriptions of abstract abilities including control ability and observation ability.Firstly，according to the structural elements of the closed-loop control system，we designed and generated the type of indicators modeling data samples.Furthermore，the capability variable system under the SEM framework was designed and constructed.The key parameters，such as path coefficients，outer loading and outer weights，were determined by the PLS algorithm.Then the structural and measurement equations of the obtained PLS-SEM ability model were evaluated separately.Finally，according to the spacecraft PLSSEM ability model，the various types of abilities of the control system were quantitatively described and analyzed to verify the effectiveness of the proposed modeling method.

Key words: structural equation model, partial least square method, spacecraft control system, ability model, factor analysis