The utility model discloses an electric power telecommunication engineering well cover having a security alarm function. The well cover comprises a well cover body and a fixed seat; a loose-to-trigger switch is arranged between the well cover body and the fixed seat; and the loose-to-trigger switch is connected with an alarm. When a thief opens the well body, the loose-to-trigger switch turns on a power supply, the alarm begins to work and a time-delay relay touches a mobile phone which has a one-key turn-on function so as to inform a worker that the well cover is stolen, so the worker can quickly judge where a well cover is stolen based on information contents, and it is easy for the worker to catch the thief. The loose-to-trigger switch can be arranged on one end of a connecting mechanism, so when a thief disassembles bolts, the loose-to-trigger switch turns on the power supply, the alarm begins to work, the time-delay relay touches the mobile phone to inform the worker that the well cover is stolen, so the worker can quickly judge where a well cover is stolen based on information contents, and it is easy for the worker to catch the thief.