Hydrogen gas concentrations and jet velocities were measured downstream by a high response speed flame ionization detector and PIV in order to investigate the characteristics of dispersion and ignitability for 40 to 82 MPa high-pressurized hydrogen jet which was discharged from the nozzle with 0.2mm diameter,. The lights emitted from both OH radical and water vapor species yielded from hydrogen combustion ignited by an electric spark were recorded by two high speed cameras. From the results, the empirical formula concerning the relations among time-averaged concentrations, concentration fluctuations and ignition probability were obtained to suggest that the relations would be expressed independent of hydrogen discharge pressure.