The invention discloses a method for controlling the amount of remaining oxygen in a powder injection preparation, and the method comprises the steps that nitrogen from a liquid nitrogen storage tank or a nitrogen generator enters a filter through a conveying tube to be purified; the nitrogen purified in the previous step is filled in a powder injection package bottle by a nitrogen charging head; an included angle between 15 degrees to 75 degrees is formed between a gas outlet tube and a wall of the powder injection package bottle in the nitrogen charging process; and the bottle is sealed by a gland after being filled with the nitrogen. According to the method, as the included angle formed between the gas outlet tube of the nitrogen charging head and the wall of the powder injection package bottle is controlled, the nitrogen is blown out at a certain angle; the nitrogen is well charged into a container; furthermore, the nitrogen gas does not blow a powdery drug at the bottom of the bottle directly; the powdery drug is not blown out of the bottle; the method can reduce the amount of the remaining oxygen in the bottle significantly; the amount of the remaining oxygen is controlled to be less than 1.2%; and the stability of the drug is improved effectively.