Objective To evaluate the effect of mind mapping on adverse effects caused by medication via patient control alagesia pump(PCA).Methods One hundred and seventy-nine patients with PCA pump after operation were divided into control group(n=90)and observation group(n=89)according to the admission time.The observation group was nursed with mind mapping and the control group with routine method. The incidences of adverse effects caused by medication via PCA pump were compared between the two groups.Result The incidences of adverse effect in the observation group and the control group were 19.1%and 32.2%respectively,with statistical significance(P<0.05).Conclusion Nursing with mind mapping for medication via PAC pump can improve nurses’clinical ability in observation and nursing and therefore effectively prevent and deal with adverse effect caused by medication via PCA pump to relieve patients’pain and improve nursing quality.