Palladium film hydrogen sensor based on suspended micro hotplate has been fabricated to operate at elevated temperature with low power consumption. Below 150 degrees C, the response of the sensor to H-2 is represented by an increase in resistance. At higher temperature, the phenomenon of resistance reduction appears when it comes into contact with H-2. We have researched the reasons for this phenomenon and proposed that the sensitive mechanism is the redox reaction of Pd film on the suspended structure. The suspended substrate can affect the temperature at which redox of the Pd film occurs, and be sensitive to the changes of the surrounding gas stream. When the working temperature is 400 degrees C, the magnitude of response (S) changes to -0.4% within 2 s for 200 ppm H-2, and S changes to -3% within 10 s for 4000 ppm H-2. This micro hotplate based hydrogen sensor can control the range of operating temperature according to the performance requirements. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.