The invention discloses an automatic angle adjustment mechanism for an interferometer, and an angle control method of the automatic angle adjustment mechanism. The automatic angle adjustment mechanism comprises a clamp platform, wherein a clamp vertical plate base and a clamp vertical plate are arranged on the clamp platform, the clamp vertical plate base is fixedly connected on the clamp platform, the clamp vertical plate is connected on the clamp platform in a rotated manner, an elastic member used for driving the clamp vertical plate to rotate toward a deflection direction is connected between the clamp vertical plate and the clamp platform, a driving motor, an angle sensor and a control system are further connected on the clamp platform, the driving motor is used for driving the clamp vertical plate to rotate, the angle sensor is used for acquiring a rotating angle of the clamp vertical plate, and the control system is used for comparing the acquired rotating angle with a pre-input deflection angle so as to perform feedback adjustment control on a driving stroke of the driving motor. The automatic angle adjustment mechanism and the angle control method thereof replace the existing manual adjustment and comparison based on experience with automatic control and adjustment, and improve the efficiency and precision of angle adjustment.