OBJECTIVE： To explore the role of clinical pharmacists in the treatment of critical patients at perinatal stage. METHODS： During the treatment process of 4 critical patients at perinatal stage， according to the patients’ special pathophysiologic status （such as urea cycle disorder， dyslipidemia， severe infection， can not recover circulating blood volume rapidly， etc.）， weighing the order of priority， based on relevant guidelines and literatures， clinical pharmacists provided individual medication advices in respects of drug selection， medication timing， treatment course， drug combination and dosage adjustment， such as using cefuroxime， reduced glutathione， ursodesoxycholic acid， etc.， stopping drugs timely or adjusting antibiotics therapy plan. They also provided pharmaceutical care as lab index determination and ADR monitoring. RESULTS： Physicians adopted clinical pharmacists’ advices， and then 4 critical patients were all recovered. CONCLUSIONS： During the treatment course of critical patients at perinatal stage， clinical pharmacists should select safe and effective drugs as much as possible and adjust therapy plan in time according to clinical symptoms. When the security runs counter to effectiveness， clinical pharmacists should fully weigh the advantages and disadvantages and guarantee the maximum safety of pregnant or delivery women and fetuses.