A sensor fabrication method and a sensor, the sensor fabrication method comprising gas-sensitive and humidity-sensitive device forming steps; The gas-sensitive and humidity-sensitive device forming steps comprise a device region forming step and a device forming step. The device region forming step comprises a humidity-sensitive device region (11) forming step and a gas-sensitive device region (12) forming step. The device forming step comprises a humidity-sensitive device forming step and a gas-sensitive device forming step. A humidity-sensitive capacitor and a gas-sensitive resistor are made on a same silicon wafer (1) by a completely compatible process without requiring a special process, so that the structure is simple and reliable. A gas-sensitive material (10) is injected and formed by using a self-alignment process, so that a gas-sensitive pattern is stable and the size is consistent. The gas sensitive material (10) that only needs to be treated at a low temperature below 400°C is compatible with a conventional semiconductor aluminum wiring process, wherein there is no need to use precious metals such as gold, and beneficial effects such as cost reduction may be achieved.