The invention discloses a method for welding an aluminum and steel plate for ships.The method includes a), machining weld grooves to obtain V-shaped grooves with groove angles of 60 degrees, and cleaning the grooves and two sides of the inner wall and two sides of the outer wall of each groove until metallic luster is exposed; b), coating the grooves with paint; c), drying the paint and then preheating weld components at the preheating temperature of 150-200 DEG C; d), welding the aluminum and steel plate by the aid of laser filler wires; e), annealing the aluminum and steel plate, to be more specific, heating the aluminum and steel plate until the temperature of the aluminum and steel plate reaches 440 DEG C, preserving heat of the aluminum and steel plate for 12-14 h and cooling the aluminum and steel plate by the aid of air.The thickness of the paint spread on the grooves is 50-60 micrometers, the paint comprises, by weight, 12 parts of polyvinyl butyral, 3 parts of aluminum powder, 2 parts of ceramic powder, 25 parts of dimethylbenzene, 7 parts of diethyl ether, 11 parts of copper and zinc alloy powder and 30 parts of triphenylmethanol, and a weight ratio of copper to zinc in the copper and zinc alloy powder is 6:5.The method has the advantage that welded joints are excellent in mechanical performance after the aluminum and steel plate is welded.