Pulse Detonation Engines (PDEs) have the potential to revolutionize aerospace propulsion system for aerospace vehicles. The PDE will require the use of liquid fuels for many practical applications because liquid fuels axe denser compared with gaseous fuels. It is widely recognized that the propagation velocity of liquid fueled detonation with large droplets is significantly lower than the equivalent gas-phase Chapman-Jouguet detonation velocity. Therefore it is important to generate fine droplets. Generally liquid fuels are atomized by fuel injection nozzles which used for diesel engines of automobile and the diameters of the droplets are relatively large. In the present study the ultrasonic atomizer is applied in order to generate finer droplets for the first time. To evaluate the application to PDEs of the ultrasonic atomizer a new PDE facility has been built. Jet A-l is used as a liquid fuel and oxygen as an oxidant. The dimensions of the detonation tube axe 50 mm diameter by 2348 mm long. The hydrogen/oxygen pre-detonator is used to ignite. Experiments are performed initially at atmospheric pressure. Through the present experiments the present authors have succeeded in the initiation of detonation in atomized Jet A-l droplets which axe generated by ultrasonic atomizers.