The Shell coal gasification process in the methanol synthesis process and the system production operation were introduced. Catalyst for methanol synthesis reactor operation was summarized. The problem of catalyst deactivation  and  the too fast  change frequency were analyzed.In order to solve the above problems, a series of reformation in synthesis loop system were made. In existing synthesis tower in parallel, a new synthetic tower shared synthesis tower part load in order to reduce the catalyst production strength in the existing synthetic tower , cut down bed heat load, enhance catalyst poisoning resistance and extend the life of the catalyst.Results showed that after modification, the economic cost was reduced and 3.34 million yuan each year was directly saved.The stable operation of the devices in high load and a long period were ensured.