NiGa2O4 nanofibers were prepared by a single spinneret electrospinning method. The precursor was analyzed by TG-DSC. The as-prepared samples were characterized by XRD, SEM, N-2 adsorption-desorption, FTIR, XPS and UV-Vis DRS, respectively. The gas-sensing properties of NiGa2O4 nanofibers were investigated. The characterization results demonstrated that the one-dimensional NiGa2O4 nanofibers consisted of about 10-15 nm nano- crystals after calcination. It was found that the sensor based on NiGa2O4 nanofibers (600 degrees C, 2 h) exhibited good response and good selectivity to trimethylamine (TMA) vapor at room temperature. When operating at room temperature, the responses of the sensor based on NiGa2O4 nanofiber (600 degrees C, 2 h) to 1 ppm trimethylamine reached 1.05; the detection limit for trimethylamine was 1 ppm; especially, the response time and the recovery time for 1000 ppm trimethylamine were 14 s and 2 s, respectively; the response time and the recovery time for 1 ppm trimethylamine were all shorter than 2s. If the long-term gas sensing stability is improved, the sensor based on NiGa2O4 nanofibers (600 degrees C, 2 h) can be used as trimethylamine-sensing gas sensor in practice.