The invention relates to an improved transfusion alarm and a use method thereof. The transfusion alarm comprises a liquid level detection device and an alarming device, wherein the liquid level detection device comprises a puncture needle body, a 
prism, a first 
optical fiber, a second 
optical fiber and an 
optical fiber connecting head; and the alarming device comprises an optical 
fiber connecting seat, a 
light emitting diode, a photosensitive 
diode, a 
signal amplification circuit, a reference 
voltage circuit, a comparison circuit, a singlechip 
microcomputer, a sound-light alarm circuit, an 
electronic switch, a 
peripheral circuit and the like. The improved transfusion alarm is simple in structure, safe and reliable, low in manufacturing cost and convenient to use, and is suitable for 
mass production and large-scale use, and the working amount of nurses is not increased; a photoelectrical principle is used to detect the liquid level; the optical fibers are utilized to transmit signals to the alarming device; the transfusion alarm is high in alarming accuracy, and is not influenced by the factors such as 
medicine liquid containers and the liquid level detection device; and electrolytic reaction cannot be generated on the 
medicine liquid. With the adoption of the transfusion alarm, the liquid level detection device is separated from the alarming device; and the liquid level detection device is extremely low in cost and is disposable, so that safety is ensured; and the alarming device can be used repeatedly, and has the characteristics of 
energy conservation, environment friendliness and the like.