Pulse detonation engine (PDE) holds promise to increase performance of air breathing propulsion systems by taking advantage of high cycle efficiency due to constant volume heat addition characteristics of detonative combustion. Currently, PDE is an active research topic with experimental developments reported by many researchers. Several of these investigations attempted multiple cycle experiments, however, it is uncertain as to whether detonations were produced on a regular basis in these tests. The experimental results for development of hydrogen-fueled pulse detonation engine are discussed in this paper. Although characteristics of premixed detonation of hydrogen-air mixture are well investigated, characteristic of detonation in non-premixed or partially premixed gases has not been studied yet. As the first step, a single cycle test was conducted to research of deflagration to detonation transition (DDT) of hydrogen / air directly injected to combustion chamber. As the second step, a multiple cycle test up to 10 Hz was conducted to demonstrate the feasibility of multiple cycle operation of PDE. Thrust wall pressure, tube wall pressure along the tube, and ionization current were measured. Sharp pressure spike was observed. It shows that the overdriven detonation wave was formed at thrust wall. The injection systems were also studied for single injection and double injection. It should be noted that, although the detonation waves could not be initiated instantaneously at the igniter, the resulted impulse on thrust wall could be improved by double injection system as compared with single injection system.