AbstractPresent status of ignition and high-gain target design is presented. A simple scalings of target design by one-dimensional hydrodynamic code is shown in the range from 1 kJ to 10 MJ of driver energy. The sensitivity of the pellet gain is studied with a two-dimensional code and the Rayleigh-Taylor growth factor is evaluated. It is concluded that the mixing may play an important role even in the present high-gain target design. As a way to ignite a mixed, compressed core externally, we have studied an ignition condition for the fast ignition scheme with two dimensional hydrodynamic code. Requirement for heating the spark is discussed to find the energy and duration of heating pulse.