Supercritical water reactors will continuously produce fine particulate matters during operation and accident conditions, and the deposition and movement of these particulate matters are likely to cause deterioration of heat transfer, which will affect the heat transfer and safe operation of the reactor. The grey correlation analysis method is used to calculate and analyze the particulate matter concentration distribution at different heights of the supercritical water reactor coolant channel model. The correlation of coolant temperature, axial velocity and turbulent kinetic energy to the concentration distribution of particulate matters and their respective weights in the correlation were studied. Using grey correlation to calculate, Finally, it was obtained that when the coolant channel height of the supercritical water reactor was 0.3m, 0.5m and 0.7m, the correlation order of the concentration distribution of particulate matters among the three was: coolant temperature > coolant turbulent kinetic energy > coolant axial velocity. The coolant temperature always has the relatively greatest influence, while the influence of the coolant turbulent kinetic energy and the axial velocity of the coolant is relatively small and tends to be consistent; The three influencing factors have little difference in the overall impact of the particulate matter concentration distribution, and the maximum weight difference among the three was 7.22%.