The invention discloses a method for producing a liner barrel of a solar water heater, which comprises a step of connecting screw threads with a liner plate by punching, a steps of folding the liner plate and pressing the opening of the liner plate to close the opening to make the liner barrel, and a step of connecting the liner barrel with two liner bottom winding plates by rolling. The production method can avoid generating harmful materials that threaten the health of people in a processing process, avoid secondary pollution and make water clean. After the barrel is formed, the connection is more reliable, hidden dangers brought by insufficient solder are avoided, production efficiency is improved and production cost is reduced.