We demonstrated GaN-based photonic crystal (PC) nanobeam cavities by using the e-beam lithography and the suspended nanobeams were realized by focused-ion beam (FIB) milling. One resonant mode was clearly observed at 411.7 nm at 77K by optical pumping. The quality factor was measured to be to 7.4 × 10 2. Moreover, the degree of polarization value was measured to be 40%. The temperature-dependent characteristics were measured and discussed, which unambiguously demonstrated that the observed resonant peak originated from the band-edge mode of the onedimensional PC nanobeam.