For the thick plate box K-joint component of Malaysian signature tower project,the welded joint form and welding groove sequence are optimized. Considering the local cushioning effect of welded joints,the first weld in each layer starts from the side of the flange. In order to control the welding heat input,a combined welding method of flux-cored wire gas shielded welding and submerged arc welding filling cover is adopted for the welds of main part. The welding sequences of the main weld and K joint are well-designed. Preheating, post-heat and interpass temperatures are strictly controlled to prevent lamellar tearing and guarantee the delivery quality of project components.