In order to use high phosphorus oolitic hematite as a new raw material for steelmaking, the particle size of high phosphorus oolitic hematite and reaction temperature on the preparation of iron carbide are studied in H2-CH4 atmosphere. The weight loss of sample in reduction process, phase composition of high phosphorus oolitic hematite and carburization products are investigated by means of thermogravimetric method, SEM-EDS and XRD. The SEM-EDS and XRD analysis show that the main compositions of high phosphorus oolitic iron ore are hematite and quartz, and the main microstructure is oolitic clusters with the zonal distribution of hematite and apatite. According to the experiment results, the reaction activation energy of high phosphorus oolitic hematite with size in the range of 120~160 mesh is the lowest. In reduction step, the reaction activation energy is 44.95 kJ/mol, and the apparent reaction activation energy is 9.71 kJ/mol in carburization step. From the perspective of reaction rate, the optimum temperature for preparing iron carbide from high phosphorus oolitic hematite is 1 023 K and the optimum particle size is 120~160 mesh. Generally, compared with iron ore particle size, temperature has much more influence on the iron carbide formation from high phosphorus oolitic hematite.