A wireless alarm system for transfusion security is designed based on MCU of MSP430 of TI,which can realize the automatic and real time monitoring of transfusion situation.The analog signal sampled from pressure sensor is amplified by OPA2335 and then converted into digital signal by ADS7818.The status of transfusion is monitored by using MSP430,which will generate and send alarm signal via wireless transmission system.The alarm signal is received by the paired receiving part,and is decoded to show the room and bed number of the patient with transfusion anomalies.Featured with small size,low power consumption,long transmitting distance and stable performance,this system has practical value and can be promoted in medical applications.