In this paper, we demonstrate a hydrostatic pressure sensor based on a liquid filled solid-core photonic crystal fiber (PCF). A single cladding hole of the PCF is selectively filled with the assistance of femtosecond laser micromachining. The filled PCF presents several loss dips in the transmission spectrum due to the resonant couplings from the core mode to the LP11 liquid modes. Pressure measurement is performed by monitoring the wavelength shift of the dips. The pressure sensitivities are -0.452 and -0.621nm/MPa for two of them, respectively.