A medication preparation device and method for a vial. The device comprises a control system and a double head syringe (2) provided on a base (1). A catheter I (22) and a catheter II (23) connected to the syringe (2) are connected to a needle I (3) for being inserted into a vial (01) and a needle II (4) for being inserted into an infusion bag (02), respectively. The catheter I (22) is provided with a clasp member I (5). The catheter II (23) is provided with a clasp member II (6). The control system is communicatively connected to a linear reciprocating motion mechanism I (11), the clasp member I (5), and the clasp member II (6). Compared with the low efficiency of the method in the prior art of manually holding a syringe to suck the medicinal liquid or powder contained in a vial, and then manually holding an infusion bag to insert the syringe into the infusion bag and inject the medicinal liquid therein, and the potential danger of the method in the prior art to a medical staff who operates, the device is simple in structure, occupies small space, and is simple to operate the invention automates and facilitates preparation and injection of the medicinal liquid or powder in the vial, effectively avoids backflow of the medicinal liquid, effectively reduces the labor intensity, has high medication preparation efficiency, and is secure.Dispositif et procédé de préparation de médicament pour un flacon. Le dispositif comprend un système de commande et une seringue à double tête (2) disposée sur un socle (1). Un cathéter I (22) et un cathéter II (23) relié à la seringue (2) sont reliés à une aiguille I (3) pour être insérés dans un flacon (01) et à une aiguille II (4) pour être insérés dans un sac de perfusion (02), respectivement. Le cathéter I (22) est pourvu dun élément de fermoir I (5). Le cathéter II (23) est pourvu dun élément de fermoir II (6). Le système de commande est relié en communication à un mécanisme de mouvement alternatif linéaire I (11), à lélément de fer
