The invention discloses an isolation circuit breaker with a built-in electronic voltage transformer. The isolation circuit breaker is characterized by comprising an arc extinguish chamber sleeve, an intermediate flange, an epoxy resin tube, a membrane paper capacitor voltage divider, a support sleeve, an insulated pull rod, a support sleeve wall inner signal line, a support sleeve wall outer signal line, a support sleeve bottom flange, a seal terminal, a remote module, an optical fiber and a merging unit, wherein the arc extinguish chamber sleeve and the support sleeve are connected to two sides of the intermediate flange respectively; and the insulated pull rod is arranged at the axes of the arc extinguish chamber sleeve and the support sleeve. The support sleeve and the epoxy resin tube are arranged in the coaxial direction, an inner tube is the epoxy resin tube and an outer tube is the support sleeve. The membrane paper capacitor voltage divider is fixed between the support sleeve and the epoxy resin tube. An output signal of the membrane paper capacitor voltage divider is output through the seal terminal by employing the support sleeve wall inner signal line and is output to the remote module. The remote module converts the output signal of the membrane paper capacitor voltage divider into a digital signal and conveys the output signal to the merging unit through the optical fiber.