The invention discloses a single-vector hydrophone passive positioning method based on array invariants. The method comprises steps that, short-time Fourier transform of a sound pressure signal p(t) and a horizontal vibration velocity signal vr(t) is carried out to obtain sound pressure time frequency distribution P(tau, f) and horizontal vibration velocity time frequency distribution Vr(tau, f); the sound pressure time frequency distribution P(tau, f) and the horizontal vibration velocity time frequency distribution Vr(tau, f) acquired in the first step are utilized to acquire a fuzziness plane R(tau, phi) of a normal wave pitching angle phi and a normal wave arriving time tau; target positioning is realized by utilizing the array invariant method according to the fuzziness plane R(tau, phi) of the normal wave pitching angle phi and the normal wave arriving time tau in the second step. Through the method, dependence on prior sea environment knowledge is reduced.