To investigate the heat transfer characteristics of phase change microcapsule suspensions in a circular tube, the discrete phase model (DPM) is used to simulate the flow and heat transfer of phase change microcapsule particles in the tube, and the equivalent heat capacity method is used to study the phase change process of microcapsules during the flow, and the effects of flow rate, concentration and heating power on the heat transfer characteristics of suspensions are investigated. The results show that the average local heat transfer coefficient of microencapsulated phase change material slurry (MPCS) with flow rates of 1.0 m/s, 1.22 m/s and 1.4 m/s increases with increasing of flow rate when the phase change microcapsules (PCM) is completely melted. The local surface heat transfer coefficient of the suspension increases with increasing of concentration when the MPCS with mass fractions of 2%, 5% and 8% can be completely melted. Increasing power can accelerate the melting process of PCM and allows the local surface heat transfer coefficient in the tube to reach its peak more quickly.