Catalytic performances of heteropolyacids and their salts in the condensation of formaldehyde and methyl formate to methyl glycolate and methyl methoxy acetate have been studied. H3PW12O40 and H4SiW12O40 were found to have high activities for the formation of methyl glycolate and methyl methoxy acetate. The acidic salts of heteropolyacids also showed the activities in the condensation reactions, but the neutral salts of H3PW12O40 and of H4SiW12O40 were inactive. Thermal treatment of heteropolyacids was found to show a positive effect on the catalytic activities, and the most suitable pretreatment temperature was 300 degrees C in the range 100-350 degrees C. The investigating results of the influence of the reaction conditions showed that the molar ratios of formaldehyde to methyl formate and the reaction temperatures greatly affected the reaction. It was also found that the coexistence of water in the reaction system showed a negative effect on the catalytic activity.