Abstract: The homogenized Q460GJD steel ingot for construction was multidirectionally forged and heat treated, and the effects of heating temperature (950-1 250℃) and holding time (0.5-8 h) on the austenite grain growth behavior after multidirectional forging were studied. Based on Sellars model, the austenite grain growth model was established after fitting the test data. The results show that the austenite grain size difference in as-cast Q460GJD steel was relatively large, and the mixed grains appeared. After multidirectional forging, the grain was obviously refined, and the mixed grains were eliminated. The average grain size of austenite increased with heating temperature or holding time, and the effect of heating temperature on the grain size was greater than that of holding time. The average grain size calculated by the established austenite grain growth model was in good agreement with the test value, and the relative error was less than 5%, indicating that the model had a certain reliability.