The humidity sensor based on NiI2/TPU nanofibrous membranes was prepared by electrospinning. The surface morphology and microstructure of nanofiber film were characterized and analyzed, and the humidity sensitive characteristics based on color change and resistance capacitance response were studied. The results showed that the color of the composite fiber changed from tangerine to chartreuse with the increase of relative humidity (RH) from 0% to 97% due to the color change characteristics of NiI2. In addition, the humidity sensing performance of nanofibrous membranes was measured by fitting the nanofibrous membranes on PI based interdigital electrode, which showed fast response and recovery time (0.9s/9.9s), wide humidity monitoring range (0-97% RH), lower hysteresis (1.57% RH) and excellent stability (at least 30 days).