The invention relates to a handheld 
fluorescence detector which comprises a clamping groove, a first photoelectric switch, a second photoelectric switch, a 
light source, a light 
path system, and a 
photoelectric sensor, a 
signal amplification circuit, a peak holding circuit, a 
microprocessor and an analog-to-
digital converter which are connected in order. The first photoelectric switch and the second photoelectric switch are mounted on the clamping groove and sequentially sense the 
reagent cards inserted into the clamping groove. The light 
path system comprises a first convex lens, a dichroic mirror, a second convex lens, an 
optical filter and a third convex lens; and light emitted by the 
light source sequentially penetrates through the first convex lens, is reflected to the second convex lens through the dichroic mirror, penetrates through the second convex lens and forms a 
light spot on a tested 
reagent card, and exciting light sequentially penetrates through the second convex lens, the dichroic mirror, the 
optical filter and the third convex lens to reach the 
photoelectric sensor. The 
detector is provided with a precise optical excitation and collection detection 
system, signals of the positions of the 
quality control line and the 
test line of the 
reagent card can be independently collected, the calculated amount is small, the speed is high, and the size of the 
detector can be smaller.