The preparation process for supersolidus liquid phase sintering of 15Cr series hypoeutectic high-chromium cast iron was studied. The microstructure and impact specimen fractures of the alloy were observed and analyzed by an optical microscope and a scanning electron microscope. The effect of sintering temperature on the microstructure and mechanical properties of high-chromium cast iron was discussed. Quantitative analysis of the metallographic structure was performed using a computer software to determine the correlation between microstructures and performance. The results show that the relative density of 15Cr-based hypoeutectic high chromium cast iron prepared by supersolidus liquid phase sintering is of more than 99%. Compared with ordinary cast high-chromium cast iron, the carbide of the sintered one is of a short rod shape and evenly distributed in its matrix. With the increase of sintering temperatures, both the grains of the matrix and carbides gradually grew up, and the mechanical properties of the alloy increased firstly and then declined gradually. The impact toughness and bending strength reached the maximum of 11.3 J/cm2 and 2 506.8 MPa as the alloy was sintered at 1 210 ℃ for 1.5 h. The impact fracture of the specimen is of a quasi-cleavage fracture mechanism, and the toughness is greatly improved when compared with the common cast specimens. The sintering temperature mainly affects the alloy's mechanical properties by changing the volume fraction, distribution, morphology and size of the carbides in the microstructure. The hardness of the sintered cast iron has close relationship with carbide volume fraction.