A welding method of a 7-series aluminum alloy coated thin plate for aviation comprises the following steps that 1, after a coating material and a cast ingot are attached, the distance between the periphery of the coating material and the edge of the cast ingot is 20-30 mm, fixing and welding are conducted in a bolt fastening manner every 1000-1500 mm in the length direction, and a material for welding adopts 7075-F-state aluminum alloy; 2, the composite cast ingot obtained in the step 1 is heated and hot-rolled; and 3, the plate with the thickness ranging from 7.0 mm to 8.0 mm through hot rolling is subjected to three times of cold rolling till the thickness ranges from 1.6 mm to 3.25 mm. According to the method, a spot welding mode is adopted, the plate must be packaged through steel strip in the transferring process so as to avoid the falling risk, however, in the ingot soaking process, due to the fact that the temperature is high, the steel strip is prone to leaving traces on the surface, and due to the fact that the temperature of the composite ingot is reduced in the steel strip shearing process, the two factors can cause aluminum sticking of a roller in the subsequent rolling process, the problem of rolling black lines is formed, the surface quality is unqualified, and the yield of products is reduced.