The invention discloses a surface mounted TVS device, which comprises an upper lead frame, a lower lead frame and a chip, wherein respective welding parts of the upper lead frame and the lower lead frame and the chip are located in an epoxy insulator, the welding part at one end of the upper lead frame is provided with a groove, the welding parts of the upper lead frame and the lower lead frame are electrically connected with a first metal layer and a second metal layer of the chip respectively through welding strips, and the raw materials of the epoxy insulator include the following components in parts by weight: 80-100 parts of epoxy resin, 40-60 parts of phenol resin, 75-90 parts of silicon micropowder, 5-15 parts of a flame retardant, 2-6 parts of gamma-aminopropyl triethoxysilane, 0.3-2 parts of nano silicon dioxide particles, 0.1-1.5 parts of azabicyclo, 2-8 parts of carboxylated acrylonitrile butadiene rubber, 0.3-2 parts of 2-amino-4-fluoro-1- methoxyphenyl, 0.2-1.5 parts of tri-(dimethylaminomethyl)phenol and 3-8 parts of a demoulding agent. The surface mounted TVS device can greatly reduce the bad phenomena such as punching, layering and porosity when being packaged, alsoenhances the overall mechanical properties of epoxy and effectively ensures the stability of the packaging structure.