An effectual and understandable route for the fabrication techniques of stereoscopic NO2 sensor is provided in this work. As the gas-sensing layer of the sensor, copper phthalocyanine (CuPc) grew on the top of poly(vinyl alcohol) (PVA) nanofibers (NFs). The sensitivity of the CuPc/PVA NFs stereoscopic sensors to NO2 was over 829%/ppm, while the sensitivity of the continuous CuPc films sensors was 2 orders of magnitude lower than that of the stereoscopic ones. To the responsivities at 25 ppm of NO2, the CuPc/PVA NFs stereoscopic sensors were about four times stronger than that of the continuous CuPc films sensors. For the recovery time, the CuPc/PVA NFs stereoscopic sensors were over eight times faster than the continuous CuPc films sensors. This general tactic can be used to prepare various toxic gas sensors to improve the overall performance of the devices.