The invention discloses a preparation method of a penehyclidine hydrochloride powder injection for injecting, which belongs to the field of medicinal supplies. The method comprises the following process steps of: dissolving a penehyclidine hydrochloride bulk pharmaceutical into a solution of absolute ethanol-absolute ether, adding an appropriate amount of active carbon for decolorizing, rough filtering for decarbonizing, and filtering with a microporous filtering film of 0.22 mum to obtain an aseptic and clear solution; in an aseptic environment, crystallizing the aseptic and clear solution of the penehyclidine hydrochloride, filtering an obtained crystal, washing, draining and drying; and detecting moisture and content, detecting aseptic state, charging into a sterilized penicillin bottle, covering with a butyl rubber plug, and rolling an aluminum cover to obtain the penehyclidine hydrochloride powder injection. Due to the adoption of the preparation method, a preparation is more stable on the aspects of pH value, relevant substances and content, the toxicity is lower, and the safety and effectiveness of the penehyclidine hydrochloride and the quality of a product are ensured more easily.