The invention discloses an oceanographic engineering complex node multi-robot welding cooperative control method which comprises the following steps: Step 1, importing a model, and performing weld joint point selection and information extraction, Step 2, calculating a weld joint equation, Step 3, selecting one weld joint of a main welding robot, Step 4, selecting one weld joint of an auxiliary welding robot which works at the same time, Step 5, discretizing weld joint coordinates, Step 6, performing coordinate conversion on main and auxiliary weld joints under a global coordinate system, Step7, performing inverse motion calculation on the main and auxiliary weld joints to obtain joint corner data of the main and auxiliary welding robots, Step 8, repeating the Step 3 to the Step 7 until all calculation is completed, and Step 9, generating a welding robot motion instruction to realize cooperative welding of the welding robots. According to the method, the welding efficiency is improved,the welding cost is reduced, the operation process is simplified, the welding quality is improved, and the multi-robot welding cooperative control method is easy to operate, visual in result, stable,reliable and wide in adaptability.