Abstract: Based on the characteristic analysis of the laser single-pulse energy, force analysis of the lightcraft is done. For the minimum single-pulse energy, the minimum mean thrust, and the minimum impulse, the design methods are proposed. The equation of motion of the lightcraft is deduced during the vertical movement, and the velocity and displacement are calculated. The effects of air drag, friction drag and lightcraft mass on flight velocity and the mean thrust are discussed. The quantitative results indicate that flight velocity is independent of air drag; when the friction drag becomes larger, the flight velocity becomes smaller; the minimum single pulse energy needed for flight mission would increase as the lightcraft mass increases.