Based on the schlieren method, the characteristics of hydrogen jets were tested on a constant volume injection device under different injection pressures and ambient pressures. The hydrogen jet characteristics of outward-opening nozzles and the variation laws of injection parameters were studied. The results show that the near-field of hydrogen jet presents a conical structure and forms a jet trajectory and the far-field of jet gradually develops into a large-scale spherical vortex structure. With the increase of jet pressure, axial and radial penetration distances increase and entrainment rate reduces; while increasing background pressure will show the opposite trend. The jet cone angle gradually decreases from 80° and becomes stable at close to 22°, and willnot be affected by jet pressure or background pressure. According to the normalization analysis, it is found that the penetration distance has a good self-similarity under different boundary conditions and the self-similarity coefficient (x/y) gradually approaches about 0.59. The radial diffusivity is also better than that of single-hole nozzle. Reasonable use of hydrogen jet characteristics can optimize the mixture formation of direct injection hydrogen engine, which provides a basis for the injection strategy optimization of outward-opening nozzle.