Abstract: Multi-function artificial intelligence crawler(MAIC-1) was developed in order to inspect the welding of block construction of hull. The TOFD inspection procedure for the welding was introduced, and the architecture of MAIC-1 was designed according to the procedure. Modular machine, electronics and software development were researched. The performance of MAIC-1 was tested on a steel frame, and the crawler was applied in butt welding of plates. The obtained results obtained showed that MAIC-1 with characters of using convenience, high efficient and testing stable could accomplish TOFD inspection for the welding of block construction of hull without scaffold.