In order to study the slow-light effect in the microfiber based resonator,a microfiber double-knot resonator with a parallel structure was designed and fabricated.Based on the theories of the ring resonator and the direction coupler,the theoretical model of the microfiber double-knot resonator with a parallel structure was proposed,the direction of the light-field propagation and coupling in the resonator was analyzed,the mathematic expression between the output light and the input one in the resonator was deduced,and the expression of the group delay time was also obtained.By numerical simulating method,the spectra of the transmission and the group delay time were given,the corresponding relationship between group delays and resonant wavelengths of the transmission spectrum in the resonator was analyzed.The numerical result indicates that a large group delay can be obtained at the resonant wavelength with a large extinction ratio in the resonator.In experimental,a microfiber double-knot resonator with a parallel structure was fabricated,the transmission spectrum of the fabricated resonator was well consistent with the theoretical simulation, indicating that the theoretical analysis is correct.Employing the pulse-delay method in the Oscilloscope,a measuring system of the slow-light delay in the resonator was set up.A group delay of about 75 ps in the fabricated resonator is achieved,which is larger than the reported value.The resonator could be beneficial to applicating in data delay lines,optical switches and optical memories,etc.