NOVELTY - A sol preparing method involves adding ethyl orthosilicate to a low ester alcohol solvent, and stirring and uniformly mixing the mixture. The obtained mixture is added with water and pore forming agent Triton X-100 and mixed uniformly. Alkyl siloxane is added to the reacted solution and uniformly mixed. The mixed solution is continuously reacted for 2 hours at temperature of 60 degrees C to obtain silicon dioxide polymer sol. pH stabilizer is added to the silicon dioxide polymer sol. The added product is uniformly mixed to obtain the product.    USE - Method for preparing sol utilized for stabilizing properties of a solar glass anti-reflection film.    ADVANTAGE - The method enables reducing subsequent reaction rate of the sol and improving stability and storing time of the sol. The coated film is cured and heated during subsequent thermal process in an easy manner.    DETAILED DESCRIPTION - A sol preparing method involves adding ethyl orthosilicate to a low ester alcohol solvent, stirring at a rate of 300 revolution per minute and uniformly mixing the mixture. The obtained mixture is added with water and pore forming agent Triton X-100 and mixed uniformly. An organic acid or inorganic acid is added to the obtained mixture to regulate pH of the solution between 2 and 3. The obtained solution is reacted for 4 hours at temperature of 60 degrees C. Alkyl siloxane is added to the reacted solution and uniformly mixed. The mixed solution is continuously reacted for 2 hours at temperature of 60 degrees C to obtain silicon dioxide polymer sol for antireflection film, where weight percentage ratio of ethyl orthosilicate, low ester alcohol solvent, water, Triton X-100 and alkyl siloxane is 1-20: 50-85: 10-20: 1-5: 2-10. A pH stabilizer having pH between 6.8 and 7.8 is added to the silicon dioxide polymer sol, where weight percentage ratio of polymer sol to the pH stabilizer is 0.1-0.5. The added product is uniformly mixed to obtain the product. The pH stabilizer is obtained by mixing weak acid and salt with metal ions having same weak acid radicals in water according to a certain proportion till the pH value of the solution is between 6.8 and 7.8.