The basic principle of pressure optical fiber vector hydrophone made of thin-walled cylindrical shell is described. The Michelson interferometer is used to measure the acoustic pressure signal. The Jones matrix theory is used to analyze the reasons for the decline of polarization of interference, and the decline of polarization is compensated by Faraday mirror. This optical fiber vector hydrophone adopts the basic acoustic theory of the pressure sentence direction, and other cosine point tropism curves are simulated by computer. The theory of axisymmetric problems of quasi-static mechanics have been used to analyze back-lining structure model of the fiber optic vector hydrophone, to calculate sensitivity of acoustic pressure differential phase shift, and to obtain analytical expression. The pressure optical fiber vector hydrophone made of thin-walled cylindrical shell is designed by experiment based on the fiber optic Michelson interferometer principle. The experimental measurement of the sensitivity of optical phase agrees well with the results for theoretical analysis. The point tropism measurement is basically consistent with the simulation analysis. This provides reference for the development of the high sensitivity for the small size of vector optical fiber hydrophone.