Abstract: In order to solve the unstable and large attenuation of received signal caused by parasitic capacitance in human body communication receivers, a new detection method was proposed based on direct electro-optic modulation to detect intra-body communication signals. The method was arranged firstly to establish a system model with transfer function for intra-body communication based on direct electro-optic modulation. And then, some mathematic simulations and physical experiments were carried out to demonstrate the accuracy of the proposed model and show the channel characteristics. The physical experiments results show that the detection sensitivity of the intra-body communication method based on direct electro-optic modulation can reach −86.03 dBm within 1 MHz and 30 MHz, being better than electronic detection and electro-optical crystal modulation. The method shows a steady frequency response in the range of 1 MHz and 100 MHz.