Abstract: Based on the st raight warp and wef t threads , combined sine and st raight line of the binder yarn , a geomet ric model of 3D orthogonal fabric st ructure was established. According to the yarn cross-area confined by thebinder , non-linear equations that include fabric structural parameters as unknown quantities were set up . The approximate values were calculated and the unknown quantity in the binder yarn model was determined by a numericalmethod. Two pieces of glass fiber three-dimensional orthogonal fabrics were woven and consolidated withunsaturated polyester. The shape of the binder yarn in the manufactured composites was tested. The observed shapeof the binder yarn is in accordance with the model result . Furthermore , the binder yarn crimp factor , the fiber volume f raction of tested values and modeled ones are also compared. The results show that the established fabric geomet ric model can be used to represent the practical 3D orthogonal woven fabric structures.