Re-reflection from a wave paddle disturbs the incident waves to the model structure in the flume, In particular, it becomes serious problem in the irregular wave tests, since continuous action of several hundreds of waves must be realized in order to investigate the statistical properties. In the present paper, the principle of non-reflective wave generation is established on the basis of potential theory of wave maker.
　The principle of non-reflective wave generation is that the total wave forces acting on the both sides of a wave paddle, which is operated in non-reflective motion,always equal to the wave forces to generate original waves, when the inertia component of the wave forces can be disregarded.
　After considerations of non-reflective wave generation systemns, the thrust control system has been adopted for the new irregular wave generator in the large wave channel of 105m long, 2.5m deep and 3.0m wide. The performance tests by regular waves estiablish that the thrust control decreases considerably the re-reflection of waves and makes very stable standing waves in front of a verical wall.