Abstract: The expendable bathythermograph (XBT) is widely used in ocean temperature profile measurement. Its nationalization is important for China's ocean exploration and military applications. In this paper, the technical parameters of domestic-made and imported XBT are compared. Taking advantage of the chance of other sea trials, comparative experiment was carried out. The results show that the performance and reliability of the domestic-made XBT are as good as the imported one. The existing problems are analyzed and recommendations to further improve the domestic-made product are given.