OBJECTIVE： To reduce mistake in Pharmacy intravenous admixture service （PIVAS）. METHODS： Internal errors and external errors of arrangement area and dispensing area were collected from PIVAS of our hospital during Aug.-Dec. 2013， and types and reasons of them were analyzed. Relevant prevention measures were formulated and implemented since Jan. 2014. The errors of PIVAS were collected again during Mar.-Aug. 2014 to evaluate the effects of measures. RESULTS & CONCLUSIONS： Considering the reasons， improvement measures had been formulated， such as one drug in one basket， enlarging daily inventorying range， prohibiting cross dispensing， summarizing and analyzing monthly error. Compared with before improvement （Aug.2013-Jan. 2014）， error rate of arrangement area and dispensing area after improvement （Mar.-Aug. 2014） decreased by 41.81％ and 44.87％， decreasing month by month； various internal errors decreased and external error was eliminated. It is suggested to summarize and analyze PIVAS works regularly and formulate improvement measures， so as to reduce the occurrence of errors gradually and improve the quality of intravenous drug dispensing.