A reflecting mirror ball head clamping device comprises an adjusting rod, a ball head and a clamping support, wherein a ball socket is formed inside the clamping support and filled with the ball head; the ball head comprises a semi-spherical structure and a middle bearing rod; the semi-spherical structure comprises a top platform and a semi-spherical body which are connected in an up-down sealing manner; the middle part of the top platform is connected with the bottom end of the adjusting rod through the middle bearing rod; the ball socket comprises a socket wall and a plurality of elastic barbed claws which are arranged near the top end of the ball socket; the bottom ends of the barbed claws extend in an inclined-down manner to reach above the top platform; and in the transverse direction, the width of the top platform is greater than the maximum interval among the bottom ends of the barbed claws. The reflecting mirror ball head clamping device provided by the invention has the advantages that the clamping firmness is relatively strong, the ball head can be effectively prevented from being released, the stability of the reflecting mirror ball head clamping device is guaranteed, the vibration resistance of a headlight is strengthened, and the reliability of the headlight is improved.