This paper reports that the absorption spectra of H2O+ have been measured by tunable mid-infrared diode laser spectroscopy in the spectral range of 1100-1380cm-1. The H2O+ ions are generated in an AC glow discharge of the gaseous mixtures of H2O/He and detected with the velocity modulation technique. Forty new lines are assigned to the v2 fundamental band of H2O+((X)2B1). The observed lines together with other data published previously are fitted to the standard effective Hamiltonian of an asymmetric top, yielding a set of improved rotational constants, spin-rotation constants and their quartic and sextic centrifugal distortion constants for the v2=1 vibrational state of H2O+.