Integrated gate-commutated thyristors (IGCTs) are widely used in power electronics systems such as power converter and solid-state circuit breaker (SSCB). The higher operating temperature of the IGCT will lead to the increase in the failure rate and the reduction of the reliability. In this paper, a thermal analysis of the IGCT water-cooled heat sink for the SSCB rated for the current of 7.5 kA is described. In order to ensure the reliability of the paralleled connection IGCTs, two schemes of the IGCT water-cooled heat sink based on an S-type fluid tube and the Archimedes spiral fluid tube for the SSCB are studied. Through the 3-D finite-element method simulation, the comparison of the results shows that the Archimedes spiral fluid tube has lower thermal resistance and pressure drop under the same heat power condition and the water flow rate. Finally, the corresponding test results indicate that the junction temperature of the IGCTs will not exceed 100 degrees C by using the water-cooled heat sink based on the Archimedes spiral fluid tube, which can meet the design requirement.