The principle and experimental results of laser frequency noise suppression by all- fiber ring resonator is provided. A saturated absorption spectroscopy and fiber ring resonator double-loop-stabilization for laser frequency is realized by Pound- Drever- Hall technique. The frequency noise of stabilized laser is measured by a heterodyne Mach- Zehnder interferometer and obtain the frequency noise suppression larger than 40 dB when Fourier frequency f < 100 Hz . At 1 Hz offset, the frequency noise power spectral density of stabilized laser is less than 100 dB Hz2 /Hz and the frequency noise suppression is 60 dB.