Based on the experimental results, a simplified model for low-voltage powerline used as a high frequency communication channel is presented.  With this model, the Orthogonal Frequency Division Multiplexing (OFDM) based high rate digital communication over low-voltage powerline is analyzed and simulated. The capability of the signal transmission system in overcoming multi-path interference and selection of the system parameters are discussed. And time-domain simulation is carried out to investigate the transmission capability of the OFDM communication system for different mapping schemes and transmission power levels. Simulation results show that it is possible to realize high rate digital communication over low-voltage powerline using OFDM when the transmitted power is large enough.