At present,the working arms of tunnel construction equipment are designed with high strength,light weight,high wear resistance and long life. For welding characteristics and requirement of the boom,developed a double location for boom welding manufacturing flexible robot welding equipment,welding trajectory through 3D off-line programming software to carry on the teaching,and used in the process of welding nozzle arc sensor,probe sensor,laser distance sensor and real-time tracking of product assembly,groove and location deviation compensation to ensure the welding quality. According to the characteristics of the boom,a set of flexible welding jig which can be used for secure and reliable clamping of all kinds of boom was designed. The optimum welding parameters were obtained by welding test and process evaluation. The flexible welding robot has been successfully applied in the manufacturing and welding production of boom products for tunnel construction equipment of our company,and the product quality and production efficiency have been significantly improved.