The invention relates to a pre-cleaning and moisturizing agent suitable for medical apparatuses, and preparation method thereof. The invention is characterized in that the pre-cleaning and moisturizing agent for the medical apparatuses is composed of a surfactant, a corrosion inhibitor, a humectant, protease, lipase, starch powder, cellulase, an osmotic agent and an enzyme stabilizer. The pre-cleaning and moisturizing agent has no irritating odor, is safe, low in toxicity and corrosion, free of chemical residuals, stable in performance and convenient to use, can be used for pre-cleaning and moisturizing surgical instruments, microsurgical instruments, flexible endoscopes, dental instruments, minimally invasive surgical instruments, rigid endoscopes and high frequency instruments and the like which are prepared from stainless steel, alloy of the stainless steel, copper, rubber and other materials.