The invention relates to a dehydration method of a roller washing machine. The method comprises two parts, namely, the preliminary dehydration part and the final dehydration part; each part is characterized in that weighing detection is carried out after eccentric detection of the traditional roller washing machine; different weighing intervals are set according to different model platform of the washing machine; each weighing interval corresponds to a standard eccentric value; when the weighing detection result is within the set weighing interval, the eccentric value is detected again and compared with the standard eccentric value, thus to control the rotating speed of a motor to dehydrate. According to the method, eccentric detection of the two dehydration parts is carried out at four times, the load weighing detection is performed, and thereby, the dehydration function of the roller washing machine can be realized well, and the noise, vibration, safety, service life and other performances of the whole washing machine are improved.