In order to reduce the burden on medical staff and ensure the safety of patients, a distributed monitoring device for wards is designed. It realizes the automation and intelligence of the ward transfusion monitoring on the basis of the wireless communication technology and the light refraction and scattering principle. The infrared ray transmitted by infrared transmitter (IR908) is received by infrared receiver (PT908) through the infusion tube, the change of liquid in the infusion tube could alter the receiving light intensity which leads to the voltage change of the infrared receiver, and the SCM identifies the voltage of infrared receiver finally. The experimental results show that the device has simple structure, high reliability, low cost, which realizes the automatic monitoring for a long time.