The invention relates to a degradable medical tissue protecting and cleaning fluid and a preparation method and application thereof. The protecting and cleaning fluid is colorless, transparent and viscous and comprises, by weight percentage, 0.1-10% of hydrophilic antibacterial raw material which mainly refers to derivatives of chitosan, 0.5-5% of hydrophilic moisture retaining raw material which mainly refers to starch derivatives, and physiological equilibrium liquid which mainly refers to 0.9% of sodium chloride, and phosphate buffer solution (PBS). The hydrophilic antibacterial raw material, the hydrophilic moisture retaining raw material and the physiological equilibrium liquid are physically mixed to form the medical tissue protecting and cleaning fluid.