The invention discloses an underground safety lamp for a power cable working well. The underground safety lamp comprises a shell, a lampshade connected with the shell, an installation plate, a support, a storage battery, an LED lamp set, a gas sensor set and a controller. The installation plate is fixedly installed between the shell and the lampshade, the support is connected with the shell, the storage battery is arranged in the shell, the LED lamp set and the gas sensor set are arranged on the installation plate, and the controller is electrically connected with the storage battery, the LED lamp set and the gas sensor set. According to the underground safety lamp, the structure is simple, the cost is low, carrying is convenient, operation is easy, performance is excellent, the service life is long, the maintenance cost is low, good illumination conditions can be provided for on-site operation environment, the integrated gas detection function can achieve 100% real-time automatic detection and warning in the whole operation process, the safety of the one-site operation environment is effectively improved, accidents are avoided, economic benefits are improved, early-stage preparation time of power cable underground operation is effectively shortened, user power-failure time is shortened, and the awareness that power enterprises serve the society is improved.