GT-021A reverse osmosis membrane acid cleaning agent used in cleaning system fouling, microbial contamination and organic particles attached to the purpose is to improve the reverse osmosis membrane desalination rate, reduce the one or two section of the pressure difference, so as to extend the service life of the film. Low foam formulation, the pH value of the diluted liquid should be maintained at 3 + 0.5, the approval of the European Commission for environmental protection as a cleaning agent should be used in the production of drinking water in the reverse osmosis system, liquid chemicals, can shorten the mixing time.