A method of preventing priority inversion in power line communication includes generating a priority notification signal of each node in order to prioritize a packet transmitted by each of the nodes, decreasing carrier detection threshold value of a prioritization section in the priority notification signal of each of the nodes, increasing transmission power level of the prioritization section in the priority notification signal of each of the nodes, transmitting the priority notification signal generated by each of the nodes, prioritizing the nodes by comparing the prioritization sections of the priority notification signals, and preferentially transmitting a packet of a node with a higher priority. This can solve a priority inversion problem between signals in a network to safely transmit signals without collisions and latency.