This letter presents a two-axis slim fiber laser vector hydrophone with a V-shaped flexed beam as a mass-spring element. Theoretical analysis and finite-element methods are both utilized to obtain the sensitivity and frequent response of the hydrophone. The key factors that determine the sensitivity and resonant frequency are discussed. The experimental results show an acceleration sensitivity of 39.2 and 53.2 pm/g at the x-, y-axis, respectively, a resonant frequency of about 310 Hz, and a directional resolution larger than 20 dB.