The invention relates to a disposable medical sterilizer. The sterilizer comprises a liquid medicine tank used for containing sterilizing liquid, a middle body and a protective sleeve, wherein the top end of the liquid medicine tank and the middle body are rotationally buckled fixedly, and the top end of the middle body and the protective sleeve are rotationally buckled fixedly. A liquid leaking hole is formed in the top end of the middle body. A plugging pin matched with the liquid leaking hole in size is arranged in an inner cavity of the protective sleeve. In the state that the middle body and the protective sleeve are tightened, the liquid leaking hole is plugged by the plugging pin, and the middle body and the liquid medicine tank are sealed. Compared with the prior art, the disposable medical sterilizer is simple in overall structure, low in manufacturing cost, more convenient to use, reliable in sealing performance, convenient to carry, capable of achieving sterilizing wiping of small wounds, safe, sanitary, free of secondary infection of wound portions, economical and practical.