<p>By means of microstructure observation, x-ray diffraction, hardness measurement, and friction and wear tests, the effects of induction and integral heat treatments on the microstructure and mechanical properties of HT300 gray cast iron were studied. Results indicate that the microstructure of the as-cast iron consists of uniform pearlite, while after induction or integral heat treatments, the microstructure is primarily composed of high-hardness twinned martensite. Compared with the integral heat treatment, induction-heat-treated gray cast iron has a higher graphite content, more uniform microstructure, and the hardness is higher with the maximum surface hardness of 894.47 HV_0.2, whereas the surface hardness of the cast iron after integral heat treatment only has the maximum value of 730.50 HV_0.2. Both heat treatment methods enhance the wear resistance of the gray cast iron. Among them, the integral-heat-treated gray cast iron has a stronger graphite lubrication ability during wear, while for the induction-heat-treated gray cast iron, the hardness and phase transformation of the matrix phase are more prominent. These factors resulted in comparable wear resistance between the two heat-treated gray cast iron.</p>