Abstract: A broad-bandwidth analog optical fiber transmission system was developed for ultra-fast pulse signal transmission under the circumstance with complicated electromagnetic field. The ultra-fast pulse electric signal was converted to optical signal by means of electro-optic conversion. After several kilometers distance transmission, the optical signal was recovered by means of photo-electric conversion. The experimental measurement results of the system indicate that its bandwidth is (0.0003~3)GHz, in-band flatness is 1dB, linear dynamic range is 40dB(100 multiples), output peak-to-peak noise is less than 5mV, input standing-wave-ratio is less than 2. It's applied in high power microwave experiments. The results show that the 3GHz analog optical fiber transmission system which employs electro-optic and photo-electric conversion technology is suitable for ultra-fast pulse signals transmission in radiation field diagnosis.