Embodiments of the present invention disclose a battery switch on circuit and a lithium battery. The circuit includes a communication control module, a relay, a communication control circuit, a switch, and a communication connection terminal. A communication signal terminal of the communication control module is connected to a first contact of the relay, a common contact of the relay is connected to the communication connection terminal. A coil of the relay is powered on to control the common contact and the first contact to be gated and is powered down to control the common contact and a second contact of the relay to be gated. The communication connection terminal is configured to connect to an upper computer. The switch includes a first terminal, a second terminal, and a control terminal. A signal from the control terminal of the switch is capable of controlling conduction or disconnection between the first terminal and the second terminal. The first terminal of the switch is connected to a power supply, the second terminal of the switch is connected to a power input terminal, and after the power input terminal is powered on, the coil of the relay is powered on. A signal input terminal is connected to the second contact of the relay, and a control signal output terminal is connected to the control terminal of the switch. Whereby, an effect of normal power-on and communication after the entire circuit is powered off is realized.