A gas sensor with low power consumption was manufactured using a suspended micro-hotplatform (MHP) fabricated by MEMS technology. Tin oxide nanoparticles, synthesized by the hydrothermal method, were deposited on the MHP by dip coating in the form of slurry. The obtained SEM images indicated that nanoparticles were well connected and uniform in size. The gas sensing performance was also investigated in both dynamic and static test systems. In the dynamic test system, the response (Rair/Rgas) of the sensor exhibited a representative linear relationship with hydrogen at a power of 14.42 mW and changed from 1.17 to 4.51 at 5 to 100 ppm hydrogen. In the static test system, the sensor demonstrated an obvious response to ethanol, ammonia, and glycol; the response to the target gas of ammonia at a concentration of 120 ppm reached up to 23.94. The power consumption of the sensor was only 16 mW with a platinum (Pt) heating resistor at 255 ℃.