An auxiliary valve actuating mechanism of an engine includes a first valve actuating mechanism and an auxiliary valve actuating mechanism. The auxiliary valve actuating mechanism comprises an auxiliary cam, an auxiliary rocker-arm shaft, an auxiliary rocker arm, an eccentric rocker arm bushing and a bushing actuation device. One end of the auxiliary rocker arm constitutes a motion pair with the auxiliary cam and the other end is above the valve. The bushing actuation device actuates the eccentric rocker arm bushing to rotate between an operating position and a non-operating position.