The embodiment of the invention relates to the technical field of an engine and discloses a mounting structure for a high-pressure oil pump. The mounting structure comprises an engine main body and a timing chain wheel, wherein the timing chain wheel is fixedly arranged on the engine main body; a mounting hole is formed in the engine main body; a chain wheel through hole with a spline structure on the inner wall is formed in the timing chain wheel; a spline sleeve is fixed at one end of a high pressure oil pump driving shaft; one end of the high pressure oil pump driving shaft fixed with the spline sleeve penetrates through the mounting hole and is connected with the chain wheel through hole through the spline; and the high-pressure oil pump is detachably and fixedly connected with the engine main body. The mounting structure for the high-pressure oil pump is convenient to detach the high-pressure oil pump, so that the maintenance of the high-pressure oil pump is benefited and the repairing efficiency is increased. The invention also provides the engine adopting the mounting structure for the high-pressure oil pump.