Precision spectral analyzers have wide applications in high-speed optical communication, optical fiber sensing, optoelectronic device, laser radar, etc. The developments of precision spectral analysis in recent years are reviewed. At first, the principle and characteristics of Brillouin spectral analyzer based on stimulated Brillouin scattering is focused on, and then, the wavelength and optical power calibration method of Brillouin spectral analyzer is proposed. At last, the precision spectral analysis development in the future is forecasted.