Through filling CS2 into the core, a liquid-core photonic crystal fiber(LCPCF) with a fully circular air hole structure was designed The finite element method(FEM) and numerical analysis are combined to simulate the structure and optimize the parameters of the fiber. When λ = 1550 nm, the geometric optimal parameters are Ʌ = 0.75 μm, d1/Ʌ = 0.86, d2/Ʌ = 0.96, and d3/Ʌ = 0.20. Meanwhile, the LCPCF can achieve a large negative dispersion of -2697.06 ps/nm/km and a high nonlinearity of 50677.77 W-1km-1. The numerical aperture and light acceptance are 0.674 and 65.37%, respectively. By comparison, we believe that this LCPCF has obvious advantages in optical communication compensation and supercontinuum generation.