The utility model discloses a pre-tightening buckle device and an electric appliance box, the pre-tightening buckle device comprises a swing strip, a first connecting part arranged at one side of theswing strip and extending along the axial direction of the swing strip, a first clamping hook arranged at the upper side of the first connecting part, and a pre-tightening spring arranged at the lowerside of the first connecting part; wherein the second connecting part is matched with the first connecting part to form swing connection, and the second clamping hook is buckled with the first clamping hook. The closed electric appliance box is made of aluminum profiles, related components can be integrated in the independent closed electric appliance box, the sealing performance is improved, andtherefore the modular unit type optimization design of the electric appliance box is achieved. The spring pre-tightening buckle device is used for installation, the screw-free structural design of the electric appliance box cover is achieved, the attractiveness of the electric appliance box is improved, the production and installation efficiency is improved, and after-sales maintenance and the modular level are facilitated.