We propose a PCF-based interferometer by the misaligned splicing method. The PCF-based interferometers are composed of a photonic crystal fiber (PCF) and single-mode fibers (SMFs) which are spliced with lateral offsets. As the wave propagates at the first splicing point, the lateral offset will excite the cladding mode and the core mode simultaneously. As the two modes reach the other splicing point, they are recombined and coupled into another SMF. Thus, we can observe the interference pattern resulted from the phase difference between the two modes. In addition, as the length of PCF is increased, the average splicing of the interference fringes become smaller in the same measured range. We demonstrate the applications of the PCF-based interferometer as temperature, bending, and the surrounding refractive index sensors. The temperature sensitivity for the 2-cm and 4-cm PCF-based-interferometer is 3.9.~4.3pm/¢XC and 3.5~4.3pm/¢XC, respectively. As we increase the surrounding refractive index, the curves move toward longer wavelengths. Besides, the measured bending sensitivity of the PCF-based interferometer is 3.8~4.2nm/m-1. We also fabricated the liquid-filled-PCF-based interferometers by using the vacuum filling method. The measured bending sensitivity of the liquid-filled-PCF-based interferometer is 8.5nm/m-1 which is higher than that of the PCF-based interferometer. The measured surrounding refractive index sensitivity is insensitive. Thus, this liquid-filled-PCF-based interferometer can also be utilized as a sensor.