Speed and capacity of the quantum communication system can be increased by using the pulsed continuous variable entanglements with short pulse durations and high repetition rates, because the information can be encoded with individual pulses, and wavelength-division and time-division multiplexing can be applied. To avoid the saturation caused by the repetition rate of light pulses, we experimentally demonstrate a differential detection system, which is suitable for measuring the noise of pulsed lights. The photon-current difference of the two photo-diodes coupled by a transformer is passed through low pass filters to reject the repetition beat signal of pulsed light. Then it is amplified by the cascaded low-noise electronic amplifiers. The common mode reject ratio of the system is about 54 dB, and the noise of the photon-current difference is beyond that of the electronic background up to 8.7 dB when the sum of the total optical power incident to the two photo-diodes is about 0.32 mW. When the pulsed laser serves as the local oscillator, we successfully calibrate the shot noise limit by using balanced homodyne detection, showing that the detection system can be used to measure the quantum noise of pulsed optical fields.