Abstract: The paper systemically studied the distribution and genesis of hydrogen gas in natural gas all over the world on the basis of former study. The hydrogen gas content was studied for some oil and gas wells in the Jiyang Depression, and their genesis was discussed at the same time. The hydrogen gas content was very low in the Jiyang Depression. The H₂/³He value was all lower than 20×10⁶ in the wells which had R/Ra value. It was suggested that the hydrogen gas raised from mantle.