Abstract：The electronic control of direct injection fuel system，which could improve engine fuel efficiency, dynamics and engine emission performance through good atomization, precise control of fuel injection time and improvement of oil-gas mixture, is the key technology to achieve the stratified combustion and lean combustion. In this paper, a direct injection injector that based on voice coil motor was designed aiming at the technical characteristics of one 800cc two-stroke camless engine. Prior to a one - dimensional simulation model of injector was established by AMEsim and the maximal fuel injection demand was met via the optimization of the main parameters of the injector, the structure of the voice coil motor was optimized by magnetic equivalent circuit method. After that, the maximal flow rate of the injector was verified by the injector bench test while the atomization effect of the injector was verified by using a high-speed camera. The result shows that the injector voice coil motor generates the largest parameters (e.g., the electromagnetic force per unit current and the injection pressure)when the gross mass of the coil and the piston is 50g, the coil inductance is 2.5mH, the coil resistance is 2 , the rigidity of piston’s reset spring is 5N / mm and the spray cone angle is 30 degrees .Simultaneously, the spray penetration is relatively small ,the fuel injection could be up to 50mg/c and the stability of system response is the best, which satisfy the need of engine design(8000RPM)and provide the theoretical basis for the two-stroke direct injection system.