NOVELTY - Self-repairing type solar battery back film preparation involves adding a solution of self-repairing agent, urea and formaldehyde into a three-mouth flask of a reflux device, and adjusting pH value of the solution to 8. The solution is heated at 60-70 degrees C to obtain viscous transparent urea-formaldehyde resin pre-polymer. Epoxy resin, de-foaming agent n-octanol are added to the viscous transparent urea-formaldehyde resin pre-polymer to obtain a mixture. The mixture is stirred with 30-50 rotations per minute to obtain emulsion. pH value of emulsion is adjusted to 2-3.    USE - Method for preparing self-repairing type solar battery back film (claimed).    ADVANTAGE - The method enables preparing self-repairing type solar battery back film with good performance and improved efficiency in a cost-effective manner.    DETAILED DESCRIPTION - Self-repairing type solar battery back film preparation involves adding a solution of self-repairing agent, urea and formaldehyde into a three-mouth flask of a reflux device, and adjusting pH value of the solution to 8. The solution is heated at 60-70 degrees C to obtain viscous transparent urea-formaldehyde resin pre-polymer. Epoxy resin, de-foaming agent n-octanol are added to the viscous transparent urea-formaldehyde resin pre-polymer to obtain a mixture. The mixture is stirred with 30-50 rotations per minute to obtain emulsion. pH value of emulsion is adjusted to 2-3. The temperature of solution is raised to 55-60 degrees C for performing a reaction for 2-3 hours to obtain a reaction solution. The reaction solution is washed, filtered and dried to obtain micro-capsule product. Emulsifying agent is added to the micro-capsule product to obtain a mixture. Emulsifying agent is selected from sodium dodecylbenzenesulfonate or sodium dodecylsulfate. Nylon ultraviolet light absorbent, ultraviolet light stabilizer, antioxidant, self-repairing agent and toughening agent are mixed with the mixture to obtain the desired product.