In this study, the effects of calcination temperature on the characteristics of tungsten trioxide (WO3) nanofibers over time were explored. The objective being to observe the effects of calcination temperature and time of exposure on nanofibers when the voltage, work flow rate, and the pinhead used in the process were all fixed. The results showed that when the calcination temperature was increased to 550 degrees C, fiber structure was damaged. The nanofibers showed the selectivity about 9% at 360 ppm of ethanol gas. The response of ethanol will increase when the concentration increase.