Power line channel is not a typical sparse channel, but when signal to noise ratio (SNR) is low, using sparse channel estimation can improve the broadband power line communication (BPLC) system performance.The pilot pattern is crucial to the pilot-assisted estimation performance of sparse channel.An optimal pilot pattern based on the rule of minimizing the coherence of measurement matrix has been concerned in the early studies.But this pilot pattern design didnt take pilot SNR into account.In this paper, a real-time pilot placement method is proposed for the sparse channel estimation in PLC.Not only the coherence of the measurement matrix are taken into account but also the pilot SNR at the receiver.The optimal pilot pattern based on the rule of minimizing the coherence of measurement matrix is applied as the initial pilot pattern.And then some pilot positions are changed in realtime according to the PLC channel frequency characteristic.It makes a tradeoff between minimizing the coherence of measurement matrix and increase pilot SNR to give a better performance.The simulation results show that the proposed method can improve channel estimation performance in terms of both mean square error (MSE) and system bit error rate (BER) performance.