Abstract: ProCAST finite element analysis software was used to numerically simulate the filling and solidification process of K417 nickel-based superalloy ingot with large height-diameter ratio. The location, quantity and cause of the formation of secondary shrinkage defects in the solidification process of the alloy ingot, and the influence of pouring temperature and pouring speed on secondary shrinkage defects was simulated and studied, and were verified by experiments. The results show that the shrinkage defect distribution of alloy ingot obtained by numerical simulation was consistent with that of onsite casting ingot, indicating the accuracy of numerical simulation. The secondary shrinkage defects could be mitigated by increasing the pouring temperature and decreasing the pouring speed to some extent. However, the defects could not be completely eliminated. Under the condition of 1 530 ℃ and 1.40 kg·s^-1 pouring speed, the alloy ingots had the fewest shrinkage defects.