An one-off and adjustment method of hydrogen releasing from chemical hydride. The “one/off” of hydrogen release is controlled by the “contact/non-contact” procedures between the reactants. First, at least a hydride powder, a catalyst powder and a water-containing reactant are provided, and at least any two of three are mixed to form a mixture. Hydrogen gas is generated by adjusting a contact area between the mixture and the remaining one. The hydrogen-releasing reaction is terminated when a non-contacting state between the mixture and the remaining one occurs. Alternatively, an inhibitor or an inhibiting method could be used for suppressing or terminating the hydrogen-releasing reaction. The hydrogen-releasing rate could be controlled and adjusted by the extent of suppression.