Abstract: In this paper, the behavior of delayed hydride cracking in Zr-2.5Nb pressure tube material containing 60 μg/g hydrogen has been investigated. During the experiments, the DHC crack growth was monitored by the force fluctuation. The crack propagation rate（DHCR）and the threshold stress intensity factor（ KIH） were calculated later. Moreover, the influence of temperature and rolling direction was investigated. The results have shown that when the test temperature is 250℃, the rang of DHCR and KIH is 5.15×10^-8~15.14×10^-8 m/s and 16.55 ~18.49 MPa m^1/2, respectively. When the test temperature is 200℃, the rang of DHCR and KIH is 2.11×10^-8~2.36×10^-8 m/s and 26.22~30.89 MPa m^1/2, respectively. As the temperature decreases, the DHCR reduces while the value of KIH increases. When the preset crack direction is vertical to the rolling direction, the DHC phenomenon has not been observed.