Abstract: In order to study the quenching behavior and heat transfer performance of Zr-4 rodlet in water, the visualization method is employed, and the temperature history of Zr-4 rodlet is measured during the quenching process in the present study. Based on one-dimensional inverse heat conduction code, the surface heat flux and the temperature of Zr-4 rodlet are calculated, and hence the boiling curve is determined. Zr-4 experienced the following 4 stages, including film boiling, transition boiling, nucleate boiling and natural convective boiling. The effect of axial distance and liquid subcooling on the quenching behavior and the boiling heat transfer is analyzed. It is found that as the liquid subcooling increases, the quenching time is decreased, and the minimum film boiling temperature is increased. Noticeably, the transition boiling and the nucleate boiling are sensitive to the local surface conditions. A correlation for minimum film boiling temperature is developed, which is significant for reactor safety.