A multifunctional detection and alarm safety helmet comprises a safety helmet body which is provided with a helmet shell, a visor and a helmet brim. The multifunctional detection and alarm safety helmet is characterized in that the left side and the right side of the visor are provided with symmetrical grooves and connecting holes, cover plates are arranged on the grooves, each cover plate is connected with the corresponding groove in an inserting and extracting mode, one end of each connecting hole is communicated with the corresponding groove, the other end of each connecting hole is arranged on the edge of the visor, an approach electric alarm and a SF6 gas leakage detector are arranged in the grooves respectively, an inductive probe of the approach electric alarm and a detection probe of the SF6 gas leakage detector are arranged in the connecting holes respectively, a miniature fan is fixed on the visor through a screw and connected with a battery through a wire, the wire is provided with a switch for controlling the miniature fan, the front end of the helmet shell is provided with a head lamp, and the head lamp is provided with a tying strap which can be connected to the helmet shell in a sleeving mode. The approach electric alarm and the SF6 gas leakage detector have the alarm function, detection and alarm of power operation conditions can be achieved effectively in time, and the safety and reliability of power operation are improved.