The invention provides an all-fiber-pulse balanced homodyne detection apparatus. The all-fiber-pulse balanced homodyne detection apparatus, which is based on a low noise charge sensitive preamplifier, can be used to accurately measure a quadrature component of a weak coherent light field. The apparatus comprises: a 50/50 polarization-maintaining fiber coupler (1), an attenuator (2), a sensor (3), a charge amplifier (4) and a shaping amplifier (5). In the invention, the attenuator is skillfully combined with a tail fiber of the coupler so that negative factors, such as insertion loss, decrease of a degree of polarization and the like, can be avoided. Continuous accurate attenuation of light intensity can be realized. And stability is good. The detection apparatus is all-fiber, possesses a compact structure, a narrow output pulse width, low electronics noise, high quantum efficiency and can run stably for a long time.