Multi-channel narrowband filters have important applications in the field of multispectral imaging. There are many important parameters of filter optical performance evaluation, such as center wavelength of each channel, half-height full width of passband and cut-off band. It is significant to obtain the influence of spectral characteristics of narrowband filter on coating process and multispectral imaging application by accurate testing. In this work, the difficulty of spectral crosstalk in the testing process of multi-channel narrowband filters was analyzesd. A testing method, principles and equipment of measuring the spectral characteristics of multi-channel narrow-band filters based on microscopes and fiber spectrometers were demonstrated. The influence of spectral resolution on the test results was analyzed through simulation experiments. Additionally, the original data was corrected by the five-point correction method of differential operator, and the errors were also analyzed. The problems of spectral crosstalk and spectral resolution in the process of multi-channel filter testing were solved, and the results can be used to guide the production of filters and provide accurate spectral information for spectral imaging.