The invention discloses an automatic painting robot for shipbuilding coating. The automatic painting robot for shipbuilding coating comprises a painting movement mechanism, a PLC and a spray gun; the painting movement mechanism comprises a side-to-side movement mechanism, a front-to-back movement mechanism and a rotational movement mechanism; the side-to-side movement mechanism comprises a first shell, a sliding block and a first motor, the first motor drives the sliding block to move from side to side, the spray gun is fixedly arranged on the sliding block, and the first shell is provided with a distance measuring sensor; the front-to-back movement mechanism comprises a second shell, an inner shell and a second motor, and the inner shell moves back and forth in the second shell; the rotational movement mechanism comprises a support plate, a third motor and a fixed gear wheel, the side-to-side movement mechanism and the support plate are connected with the inner shell through a bearing, the third motor drives the side-to-side movement mechanism to rotate around the bearing, and the distance measuring sensor, the first motor, the second motor and the third motor are electrically connected with the PLC. According to the automatic painting robot for shipbuilding coating, the work efficiency is improved, the labor cost is reduced, the construction period is shortened, the evenness of a paint coating is good, and the quality of the paint coating is improved.