The first pair of Chinese Satellite-to-satellite Tracking Gravimetry System (CSST) was successfully launched at the end of 2021. The Attitude and Orbit Control System (AOCS) of the CSST is responsible for all kinds of attitude control and orbit control tasks which shows advanced performance than expected and guarantees the fulfillment of scheduled mission tasks. In this paper, the system configurations of the AOCS for CSST are introduced, including sensors and actuators. As a “quiet” satellite, no rotating components like momentum wheels or liquid propellants should be configured so that the configurations here are quite dissimilar from those of typical low-orbit satellites. The control modes design is discussed subsequently, which is suitable for different tasks in different mission phase, e.g., the Inter-satellite Pointing Mode for long-term mission phase and the Calibration Mode for missions of CoM calibration to the accelerometer and phase center calibration of the KBR. Algorithms are also briefly discussed here, especially the usage of the magnetorquers as the main actuators. In the end some typical results of in-orbit performance are demonstrated. All the technical requirements have been met and in some aspects its performance is better than the known results of other similar spacecraft.