Abstract: The stainless steel wire mesh was conected by micro-plasma arc butt welding under 6 kinds of joint assembly methods composed of 3 kinds of rough selvedges, and the characteristics, influencing factors of welding spot morphology and the forming mechanism of the welding spots were studied. The results show that torispherical, ellipsoid and spindle welding spot were formed during butt welding the wire mesh. The assembly methods, insert distance of rough selvedges, position of welding torch, welding heat input and distance between torch and weft on both sides of joint (the short distance X₄ and the long distance X₅) had great impact on the welding spot morphology. Torispherical welding spot was devided into a type welding spot that the weft closest to the joint did not melt and b type welding spot that the weft closest to the joint melted. When X₅ was constant, the radius of a type welding spot increased with X₄. When X₄ was constant, the radius of b type welding spot increased with X₅. When the welding heat input was constant, the long axis length of ellipsoid welding spot increased with X₄, and finally tended to a fixed value, and when X₅ was constant, the short axis length increased firstly and then decreased with increasing X₄. When the insert distance of rough selvedges was constant, the spindle welding spot volume increased with X₅. The spindle welding spot volume decreased with increasing insert distance of rough selvedges when X₅ was less than 0.33 mm, and increased with the insert distance when X₅ was greater than 0.70 mm.