Aiming at the ubiquitous dispersion problem in optical fibers currently used, a dual-core circular liquid-doped photonic crystal fiber was designed by using the finite element method and COMSOL Multiphysics simulation software. The results show that as the ratio d1/Λ of the air hole diameter d1 to the air hole layer spacing Λ decreases, the maximum change rate and dispersion of the effective refractive index gradually move to the long wavelength direction. And with the increase of the central hole diameter d2, the maximum change rate of the effective refractive index and the minimum dispersion value also gradually move to the long wavelength direction. In addition, with the increase of the refractive index nL of the doping liquid, the maximum change rate of the effective refractive index and the minimum dispersion rate also show the same changing trend. It is shown that the large negative dispersion value of －132720 ps·nm－1·km－1 can be obtained at 1550 nm for Λ=1550μm, d1/Λ=0.7, d2/Λ=0.833, and nL=1.753.