A side-hole photonic crystal fiber for (hydrostatic) pressure sensing was proposed to achieve compact and high sensitivity fiber based pressure sensor. The effective index, mode profile and the stress property of a conventional photonic crystal fiber and the side-hole photonic crystal fiber were investigated based on a full-vector finite-element method. Due to the photoelastic effect, the hydrostatic pressure induced index changes of the conventional photonic crystal fiber and the side-hole photonic crystal fiber were presented. Simulation results show that the side-hole photonic crystal fiber can achieve higher pressure sensitivity, and the pressure sensitivity increases together with the radius of big air holes of the side-hole photonic crystal fiber. Thus, the structure-optimized side-hole photonic crystal fiber can be used as a high sensitivity (hydrostatic) pressure sensor.