OBJECTIVE： To optimize the workflow of electronic pharmaceutical system （ePS）， and improve the work efficiency of outpatient pharmacy. METHODS： The problems about the application of ePS on tollying in outpatient pharmacy of our hospital were analyzed. The improvement measures were put forward and implemented. The effectiveness was summarized by evaluating relevant work indicators 6 months before and after optimization. RESULTS： Referring to main problems during the application of ePS on tollying as repetition of tallying drugs， complexity of stocking checking， low efficiency in the management of drug expiry date， deviation in the tracking of “batch/expiry”， a series of measures were carried out in outpatient pharmacy of our hospital， including optimizing tallying process， updating tracking process， adding the function of alerting the near-expiry drug， etc. The system optimization shortened the time of replenishment （26.32 s vs. 7.78 s， improving by 3.38 times） and stock checking [（165.50±5.75） s vs. （146.70±4.54） s， shortening by 11.36％]， realized accurate tracing of drug information “batch/expiry” and improved drug management [（58.00±1.88） s vs. （18.00±1.23） s， shortening by 68.97％]. CONCLUSIONS： The optimization of ePS on tallying in our hospital improves work efficiency of pharmacists and guarantees the accuracy of tracing drug “batch/expiry”.