The invention discloses a quick underwater unlocking electrical switch comprising a circuit on-off system controlled by a button. The circuit on-off system consists of a spring base fixedly arranged at the bottom of the pedestal and a sleeve arranged in the spring base coaxially in a sliding manner; and a return spring is arranged between the sleeve and the spring base to realize upward returning of the sleeve. The button is arranged in a clamp sleeve at the top of the pedestal coaxially and is connected with the sleeve by a screw rod. A normally-closed contact and a normally open contact are arranged between the sleeve and the spring base; the normally-closed contact is connected and the normally open contact is disconnected at the returning position of the sleeve; and the normally open contact is connected and the normally-closed contact is disconnected at the down pressing position of the button. Besides, a waterproof case for closing the spring base is arranged at the bottom of the pedestal; and a waterproof socket is installed at the waterproof case and is connected with the circuit on-off system by a line. On the basis of the integrated structural design, the quick underwater unlocking electrical switch has characteristics of small size, good waterproof performance and high reliably; connection and disconnection of the contacts are controlled by the button; and the unlocking and locking are carried out simply and rapidly. The switch is suitable for an underwater equipment control system needing external forces to realize switch changing.