Optical fiber filters play an important role in optical fiber communication and optical fiber lasers fabrication. Based on coupling theory analysis, spectral response of coupling optical fiber filters is tested and the relationship between tapered cycle and transmission wavelength is researched by broadband light source and spectrometer building and testing system. Experimental results show that the longer tapered cycle is, the denser peak intervals of transmission wavelength is and the more sensitive spectral response is. So optical fiber filters with different transmission wavelength and filtering gap can be produced according to the property.