Abstract: To deal with imprecise sampling length of cable harness in the layout design due to the neglect of cable physical characteristic,a new layout design method of cable harness based on physical characteristic in virtual environment is proposed.The cable tracer is fitted with Non-Uniform cubic BSpline Curve.To obtain real shape of cable harness turning corners,the bending characteristic of cable harness is considered in this model.The energy minimizing algorithm is used to solve this mathematical model in the progress of adjusting the cables.In the next step,a searching algorithm with the restriction upon cable's length is proposed to optimize the result in the last step.At the same time,an algorithm with the restriction upon the curvature of cables is proposed to adjust the cable's shape.With the help of physical characteristic in cable layout design,a more real cable shape and more precise sampling length of cable could be got.Lastly,a prototype system based on layout design of cable harness is developed and the proposed solutions are validated in this system.