Phase change material Trombe walls (PCM-TWs) have been demonstrated to be an effective means of reducing indoor heat loads. However, the heat storage efficiency is limited by the low thermal conductivity of PCMs. This study investigates a Trombe Wall Integrated with Multi-Row Channel PCM Wallboard (MCPCM-TW) to address the high thermal resistance problem in heat storage process. This study develops a visualization of solidification and melting of paraffin wax in a rectangular cavity, aimed to analyze the melting and solidification laws of paraffin wax under different heat flux. An experimental investigation was conducted to explore the storage and discharge thermal efficiencies of PCM-TW and MCPCM-TW at the same heat flux. The results show that the MCPCM-TW has obvious benefits over PCM-TW in melting/solidification with similar heating/cooling conditions. The melting process of paraffin wax can be roughly di-vided into three regimes, namely, pure conduction regime, mixed (convection & conduction) regime and convection regime. In the melting process, The MCPCM-TW enhances the heat transfer in the mix regime obviously, the melting time is reduced by 10.9%. In the solidification process, the MCPCM-TW reduces the overall thermal resistance by increasing the heat transfer areas of the internal paraffin, the solidification time is shortened by 13.19%. At the end, the per-formed experiments could be helpful for validation of future simulation with complex features, particularly to provide methods for the design of PCM walls.