In this article, the esterification of methanol with maleic anhydride has been studied. The focus was on the production kinetics of monomethyl maleate. A three neck flask with a flux condenser and stirrer was taken as a batch reactor. The temperature was maintained and controlled by a thermostat. Data of concentration and time were collected by monitoring the change of the total acid. The production rate equation of monomethyl maleate was obtained through analyzing the data, which is .