Abstract: The cause of fiber bridging and its effect on the mode I interlaminar fracture toughness G_IC are discussed and the method of isolated plies for overcoming the effect of fiber bridging is put forward in this paper.By changing the ply design of specimens,the possibility of fiber nesting is reduced to the lowest level.The calculation by FEM shows that the use of isolated plies does not change the distribution and concentration of stress in the tip of the interlaminated crack.The calculation of flexural rigidity of the specimens shows that if the ply angle of the isolated plies is ±10°~±20°,the flex-torsion coupling of specimens will be reduced to a minimum.The feasibility of this method is proved by experimental data.