Most of the research is based on the two-dimensional model instead of considering the actual situation of orbiting space vehicle. In this paper， the kinetic equations and the sliding mode control are studied to establish the mathematical model of the three-axis liquid-filled spacecraft in the three-dimensional surface and guarantee the attitude stability， which makes the modeling and the attitude control strategy more practical. First of all， the coordinate systems of actual flight environment are established， and the single pendulum model is equivalent to the sloshing of liquid fuel. Using angular momentum theorem， the inertia moment of spacecraft system with respect to the center of mass can be calculated. Based on the theorem and the Lagrange equations， the whole dynamic equations are derived and the model is established. Thereafter， it is concluded that the under-actuated system has unstable zero dynamics. Finally， considering the parameter errors of rotational inertia and the disturbance moment， a sliding mode attitude control method is designed， which can ensure the on-orbit stability of the three-axis liquid-filled spacecraft.