A surface mounting elastic sheet comprising a welding segment extended to include a fixed height encircling sidewall is disclosed and comprises the welding segment, a tongue sheet segment and a continuous fixed height encircling sidewall segment; the welding segment is used for installation of a surface on a circuit board and is provided with an upward extension end edge and an encircling side edge; the tongue sheet segment which is formed via upward bending and extension of the upward extension end edge comprises an upward convex withdrawing contact part positioned far away from the upward extension end edge and two opposite side edges which are respectively adjacent to the upward extension end edge; the continuous fixed height encircling sidewall segment which is formed via upward bending and extension of the encircling side edge of the welding segment. The continuous fixed height encircling sidewall segment comprises two fixed height side parts and a continuous supporting end edge, wherein the two fixed height side parts respectively correspond to the opposite side edges of the tongue sheet segment, and the continuous supporting end edge is opposite to the encircling side edge.