The invention relates to a method for improving the etherification degree of hexa-methoxy methyl melamine resin, which is characterized in that methylal is added during the etherification, wherein the mole ratio of the methylal to hexamethylolmelamine is 0.5-10:1. The methylal reacts with carbinol and formaldehyde, water generated during system etherification can be reduced, so that the etherification can be conducted to facilitate the generation of ethers, and the etherification degree is greatly improved. By adopting the method, the etherification degree can be improved to 5.23 from original 4.83 and the resin quality can also be improved; in addition, the water reduction in a flushing system can influence and lessen the polycondensation among molecules to cause the reduction of the viscosity of products, thus the property of hexa-methoxy methyl melamine resin (HMMM resin) can be improved greatly; for instance, the invention is beneficial to prolonging the storage term of prepared coating and improving the bond property with rubber.