Methy methoxy acetate was synthesized from methylal, i.e. dimethoxymethane, and formic acid in a tank reactor. The catalytic activities of several catalysts were tested, and toluene-p-sulfonic acid was chosen for further experiments. The effects of reaction temperature and time, reactant ratio and catalyst dosage on the yield of methyl methoxy acetate were investigated, and the optimum reaction conditions were determined as follows: mole ratio of methylal to formic acid of 0.36, mass ratio of catalyst to methylal of 1.8%, reaction temperature of 140℃ and reaction time of 4 hours. Under above conditions, the yield of methyl methoxy acetate was 87.5%.