Abstract: Objective: To study the age role in the adverse reaction of patient-controlled analgesia (PCA) by elderly hip surgical patients. Methods: The incidence of the adverse reaction was retrospectively analyzed in different age groups (60-70 years old groups and more than 70 groups years old) of elderly hip surgical patients who accepted PCA or not. Results: The overall incidence of the adverse reaction in elderly hip surgical patients was not significantly different between the ones who accepted PCA and the ones who not accepted PCA (P > 0.05). In the 60-70 years old age group,the incidence of the adverse reaction was not significantly different between the ones who accepted PCA and the ones who not accepted PCA (P > 0.05);But in the elderly hip surgical patients whose age more than 70 years old,the incidence of the adverse reaction in patients who accepted PCA was significantly higher than that in the ones who not accepted PCA (P < 0.05). On the other hand,in the elderly hip surgical patients who accepted PCA,the incidence of the adverse reaction in the ones whose age more than 70 years old was significantly higher than that in the 60-70 years old age group (P < 0.05). In the elderly hip surgical patients who not accepted PCA,the incidence of the adverse reaction in different age groups was not significantly different (P > 0.05). Conclusions: The age is an important factor led to the adverse reaction of PCA in the elderly hip surgical patients whose age more than 70 years old.