The invention discloses a high-efficient decontaminating and rust-preventing device for mechanical parts. The high-efficient decontaminating and rust-preventing device for the mechanical parts comprises an outer frame, wherein sliding sleeve slots are fixedly connected to two sides of a surface of a cross plate; a spur rack is slidably connected into the sliding sleeve slots; an internal thread sliding block is fixedly connected to the right end of the spur rack; an internal thread screw rod is slidably connected into the internal thread sliding block in a penetrating way; a fixing shaft is rotatably connected to a surface of a vertical plate; a driving rod is fixedly connected onto the fixing shaft; a semicircular gear is fixedly connected to the bottom end of the driving rod; a parts clamping device is fixedly connected to the bottom end of a limited sliding block; a movable resetting device is fixedly connected to the top end of the inner part of the outer frame and located on the right side of an oil storage tank; and a conveying pull rope is fixedly connected onto a rotary shaft. The invention relates to the technical field of mechanical processing equipment. The high-efficient decontaminating and rust-preventing device for the mechanical parts achieves the aims of automatically conveying the parts into a decontaminating chamber, reducing labor force, comprehensively decontaminating without dead corners, and improving a storage effect.