The utility model relates to an electric transmission line insulator chain tension online monitoring device. The electric transmission line insulator chain tension online monitoring device comprises an alloy steel body, a solar cell panel, an aluminium alloy circuit box, a lithium battery, a circuit board and a tension sensor. The aluminium alloy circuit box and the lithium battery both are installed inside the alloy steel body, the circuit board is placed inside the aluminium alloy circuit box; the solar cell panel is installed on the alloy steel body and connected with the lithium battery; the lithium battery is connected with the circuit board through wire connection terminals; the circuit board comprises a microcontroller LPC2880, a memory and a GPRS communication circuit; the tension sensor is connected onto the circuit board which is located inside the alloy steel body through the interface on the alloy steel body, and the circuit board is connected with a background computer through the GPRS communication circuit. The device can be used to perform full-day remote online monitoring on the tension change of an electric transmission line insulator chain, provide effective data support for background computation of electric transmission line ice coating and wind deflection situations, so that maintainers can adopt corresponding technical measures to prevent the occurrence of ice coating and wind deflection accidents.