The sensitivity of the Fabry Perot hydrogen interferometer based on Pt-WO₃ is greatly improved by using isopropanol with high thermal optical coefficient and parallel connection structure. The isopropanol cavity of the sensor is composed of a hollow fiber with an aperture of 126 μm and a single-mode optical fiber coated with silver film on its end face. The results of hydrogen sensitivity test show that the sensitivity of the interferometer in the range of 0~2% （vol%） hydrogen concentration is 1.746 4 nm/%， fast response and good reusability. Two interferometers with small cavity length difference are connected in parallel through a 2×2 coupler， and the sensitivity is amplified by using the optical vernier effect. The combined sensor has a high hydrogen sensitivity of 15.729 3 nm/% and the two interferometers can achieve temperature self compensation， which greatly reduces the temperature cross sensitivity.This research provides a useful exploration for the preparation of hydrogen sensors with high sensitivity， low cost and wide application range.