A mounting bracket for a stepless variable speed engine of a light motorcycle includes a frame, a shock absorber, an engine holder, a power connection plate and a hanger. The engine holder includes a beam and two engine fixing rods, and one of the engine fixing rods is fixed to an end of the beam by a bolt, and the other engine fixing rod is integrally coupled to the other end of the beam. The engine fixing rod has plural installation nodes coupled with the engine, and both ends of the shock absorber are hinged with the frame and the middle of the beam. The power connection plate is coupled to the engine fixing rod and has a shaft hole corresponsive with a shaft of the engine. The bolt is provided for fixing and adjusting the structural form of the engine fixing rod to facilitate adjusting the interval of the engine holder to provide a convenient and accurate installation. The bolt is provided for fixing and adjusting the structural form of the engine fixing rod to facilitate adjusting the interval of the holder to provide a convenient and accurate installation.