By a full-vector finite-element method, the dual-core photonic crystal fiber for hydrostatic pressure sensing with two layers of air holes in the cross-section missed was designed and optimized, The mode field radius and numerical aperture of the optimized dual-core photonic crystal fiber are almost the same as that of the single mode fiber, which contributes to a relatively low splicing loss between the optimized dual-core photonic crystal fiber and the single mode fiber. The calculations results show that the total loss induced by the similar mode field radius and numerical aperture is as low as about 0.026 dB, less than that between the traditional photonic crystal fiber and single mode fiber of 0.1 dB. The performance of the hydrostatic pressure sensor based on the optimized dual-core photonic crystal fiber with a length of 20 cm was studied, and the results show the sensitivity is about -1.6 pm/MPa in the range from 0 to 500 MPa.