Abstract: Geotextile tube is one kind of the geotechnical package system. It is made of woven fabric, filled with the mortar by high-pressure mud pump, and eventually becomes a tube. The geotextile tube has many advantages and wide application prospects, and it can be used for building dams and flood prevention projects. The existing theoretical calculation methods have good applicability to calculate the shape, height, tension and other parameters of geotextile tubes under the situation of high filling pressure. However, they are not suitable for the situation of low filling pressure. As the geotextile tube applied in China is often flat, and the filling pressure is low. The applicable conditions of the current dimensionless method are proposed, and the method is proved to calculate the parameters of the geotextile tube with low filling pressure. The equations are solved by numerical integration, and the results are verified and formed into charts. Thus it is easily to find the value of the parameters in actual applications.