The utility model provides an optical fiber weight measuring device comprising a trigger board (1), an optical fiber sensor (2), an optical fiber (3), a solar power supply system (4), and an optical fiber sensing demodulation system (5). The optical fiber sensing demodulation system (5) includes a light source module (6), a spectral analysis module (7), and an embedded PC processor (8). The optical fiber weight measuring device provided by the utility model is small in size, simple in internal structure, high in precision, and easy to carry.