The stainless steel sintered mesh filter element is a key component of automatic backwash filters in hydraulic, mechanical, shipbuilding, mechanical and other industries. The welding quality of its longitudinal butt weld directly affects the filtering accuracy of the filter element and the smooth operation of the automatic backwash device. It is a key link in the production process of stainless steel sintered mesh filter elements. TIG welding and special welding tools are used to weld the longitudinal weld of multi-layer stainless steel sintered mesh filter element to find reasonable welding parameters. By optical microscope, microhardness tester and energy spectrometer, the microstructure properties, solidification mode and phase composition of the weld are analyzed as well. The results show that by controlling welding heat input and improving the cooling speed of the back of the weld, the welded joint with good shape, no broken wire and no obvious defects can be obtained by TIG welding. Observing the appearance of the weld, the optimal welding current is determined to be 90~95 A. The microstructure of the weld is columnar austenite and skeleton-like ferrite, which has excellent crack propagation resistance.