Phase change energy storage technology can solve the problem of energy mismatch in time and space due to the latent heat absorption or release in phase change process. It has a wide application in solar energy utilization, building energy saving, waste heat recovery, and other fields. However, the phase change material has leakage problem in the process of use, so the phase change material is encapsulated and mixed with the single-phase fluid to prepare the microencapsulated phase change materials slurry (MPCMS). Furthermore, due to the high thermal conductivity properties of graphene oxide (GO), it was added to MPCM to improve the thermal conductivity of suspension prepared from GO as the substrate, thus further enhancing heat transfer. In this work, the heat transfer characteristics of pure water, 5wt% mass fraction of traditional MPCMS, 5wt% and 10wt% mass fraction of graphene oxide composite microencapsulated phase change material suspension (GO-MPCMS) were tested. And the effects of wall heat flux and Reynolds number (Re) on temperature distribution and heat transfer were analyzed and discussed. The results showed that, the temperature distribution of the tube wall and fluid presented the changing law of rised first, then stay flat and then rised again due to the influence of the phase change process. And under the same experimental conditions, the wall temperature and fluid temperature of suspension were lower than pure water. Both particle mass fraction and GO had great influence on heat transfer. With the same mass fraction (5wt%), the stable local Nusselt number (Nux) can be further increased by 8 percentage point when GO was added, and the Nux increased 20 percentage point when the particle mass fraction was increased from 5wt% to 10wt%. Compared with pure water, considering the influence of GO and microencapsulated particles, the average Nusselt number (Nu) of microencapsulated phase change material suspension can be increased by 1.0~2.0 times under the same experimental conditions.