A micron-scale bilayer H₂S sensor fabricated by electrohydrodynamic (EHD) jet printing in situ was evaluated. The prepared sensor consisted of a Pd@TiO₂ cover layer (porous catalytic sensing layer), a SnO₂ bottom layer (electron transport layer) and a Sn-Ti transition layer between them. The addition of TiO₂ nanoparticles to the cover layer led to a porous structure after one-step sintering. The increase in specific surface area and the formation of heterojunction effectively improved the sensor sensitivity. The PdO nanoparticles loaded on the surface of TiO₂ nanoparticles further improved the performance due to its catalysis. Since the kinetic energy of droplets of the same size generated by EHD inkjet printing is about 48 times that of inkjet printing, the film density is much higher than that of inkjet printing. The relatively dense bottom layer, and the thick and stable transition layer improved the long-term stability of the sensor. The detection limit of the sensor is 6 ppb, with linear range of 0.02-10 ppm H₂S. The response and recovery times are 7 s and 45 s (2 ppm H₂S), respectively. After 9 months of intermittent measurement, the response of the sensor to 2 ppm H₂S decreased by only 10.6%.