A CNC machining equipment for online repair of flange sealing surfaces of pressure vessels has been designed to solve the problem of repairing flange sealing grooves in large pressure vessels.This paper mainly introduces the structural design and workflow of CNC machining equipment,and proposes multiple solutions by analyzing existing problems.After the design was completed,the processing equipment was demonstrated from multiple perspectives.The results indicate that the design has basically solved the problem of online repair,providing a new solution for manufacturers and users.