With the development of human body communication ( HBC), the study and application of human electroencephalogram signals is becoming more and more extensive. Existing research is limited to non-invasive electroencephalogram (EEG) signals and limited to invasive electrocorticography (ECoG) signals. In this study, a finite difference time domain (FDTD) approach was used to build a human model and explore the transmission properties of ECoG signals. First, the signal transmission that gain at different distances between the receiver electrodes were further analyzed in the frequency range 10 MHz to 10 GHz to determine the optimal transmission frequency band for ECoG signals. Quantitatively analyze the electromagnetic energy absorbed by the human body through specific absorption ratio (SAR) to evaluate the safety of the model. Secondly, we analyze the path loss of transceivers at different distances and show the second-order exponential decay relation between the distance and the path loss. Finally, the shadowing effect of the channel is investigated. It is shown that the channel transmission gain reaches its maximum -45. 63 dB when the carrier frequency band is around 1 600 MHz and the distance between the two electrodes of the receiver is 10 mm. The resulting path loss model conforms to a second-order exponential distribution, which can more accurately describe the transmission properties of the channel.