The invention discloses a double power switching device for an acquisition terminal. The double power switching device comprises a shell, a sliding guide rail is arranged on the back of the shell, and connection terminals, a display interface and control buttons are arranged on the front of the shell. A main power voltage detection circuit, an auxiliary power voltage detection circuit, a main power switching circuit, an auxiliary power switching circuit, a microprocessor control circuit, a microprocessor power supply circuit and a main power and auxiliary power switching selection circuit are arranged in the shell. Compared with the prior art, the double power switching device for the acquisition terminal has the following advantages: the microprocessor control circuit monitors voltage signals of a main power supply and an auxiliary power supply in real time, and sends out control signals in real time, thus realizing automatic switching of the main power supply and the auxiliary power supply. Under the condition that the external power supply works but lacks a phase, the double power switching device for the acquisition terminal ensures normal working power of the acquisition terminal and avoids halt of the terminal due to non faults.