In this paper, we build a physical layer network coding (PLNC) system with adaptive pre-equalization and decode-forward transform. First, adaptive equalizers are designed at the transmitters (Alice and Bob) to compensate the distortion of channels, where pre-equalization and post-equalization share the same equalizer coefficients. The coefficients are adjusted adaptively with channels by zero forcing (ZF) criterions. The decode-forward (DF) mode is adopted at Relay to improve the system performance furtherly. Simulation results show that the superiority of the joint employment of adaptive pre-equalization and the DF mode.