Zirconium alloy fuel cladding picks up hydrogen during operation through a corrosion reaction with coolant water, which reduces the ductility of the cladding. However, there is a connection between the extent of hydride embrittlement and hydrogen concentration. The effect of hydrides formed by the gas hydrogen charging method with hydrogen content between 100~1000 μg/g on the ring tensile properties of N36 zirconium alloy cladding tubes of was investigated. It was found that the ductility reduced with the increasing of hydrogen concentration when exceeding 150 μg/g hydrogen content level, the ductility reduced to 9% when the hydrogen content was about 1000 μg/g, still remain a certain ductility. But the hydrogen concentration had little effect on the tensile strength and yield strength. The fracture pattern was found to depend strongly on the hydrogen concentration . With the increase of hydrogen , the fracture types were45°shear type fracture, cup and cone type fracture and chisel edge type fracture.