The cooperative attitude control is addressed for spacecraft formation with unreliable communication and signal quantization among spacecrafts.First,to save the data rate and bandwidth among the spacecrafts,a signal quantization communication strategy is proposed among each two spacecrafts in the formation,and a terminal sliding mode attitude control law is developed to ensure the asymptotic stability of the spacecraft formation attitude synchronization systems.Second,to compensate the effects of communication delay and signal quantization,an exponent-logarithmic sliding mode surface design is presented,based on which a cooperative attitude control strategy is developed for spacecraft formation to achieve desirable attitude in finite-time.Finally,a simulation example with four spacecrafts in a formation system is provided to verify the effectiveness of the proposed cooperative control method.