The invention discloses a safety detection method and device of liquid. The safety detection method comprises the following steps of: scanning a bar code on a vessel containing detected liquid, and searching liquid information and vessel information corresponding to the bar code in a database; acquiring first liquid information and first vessel information of the detected liquid by adopting double energy rays; when the vessel information corresponding to the bar code is matched with the first vessel information, comparing the liquid information corresponding to the bar code with the first liquid information; and when the vessel information corresponding to the bar code is not matched with the first vessel information, searching second vessel information matched with the first vessel information in the database, acquiring second liquid information which reflects an actual state of the detected liquid, and comparing the liquid information corresponding to the bar code with the second liquid information. The safety detection method has higher detection precision, and the safety detection device is more convenient to operate.