Abstract: The strains of geotextile under working conditions are all very small, generally less than 6%,according to the study of some geotextile reinforcement engineering for soft ground under embankment.An ideal mechanism of bearing force of geotextile and the prestrained reinforcement technique which causes the bearing forces and the deformations of geotextiles to approach the ideal mechanism are proposed. The results of laboratorial static model tests demonstrate that this technique has obviously improved the reinforcement effects. A method to estimate the prestrained value is also put forward .