An in vivo electric field measuring device based on quantum coherence effect disclosed in the invention belongs to the intersection field of human body communication and electric field measurement. The device provided by the invention comprises a semiconductor laser and a control unit thereof, a laser control optical path, a fiber-coupled atomic cell electric field probe and a photodetection unit, wherein the laser and its control unit respectively emit weak probe light and strong coupling light according to actual requirements; the fiber-coupled atomic cell electric field probe is used to realize the probe light and the coupling light incident on the same end of the fiber-coupled atomic cell, that is, the probe light and the coupling light are input in the same direction; the laser control optical path respectively adjusts the power, frequency and polarization state of the weak probe light and the strong coupling light; and the photodetection unit enables detection and display of EIT spectra. The device provided by the invention realizes the measurement of the in vivo electric field through the fiber-coupled atomic cell electric field probe, thereby promoting the application of the implanted biomedical system in disease diagnosis and treatment.