Abstract:To has the ability of accurate machining free curve for open numerical control system LinuxCNC, the BSpline mathematics model and its interpolation principle were studied, three BSpline curve interpolation algorithm was proposed. the moiton layer principle of LinuxCNC was analyzed, the degign steps of BSpline curve interpolation algorithm in LinuxCNC system was proposed. The experimental simulation results show that BSpline interpolation algorithm can realize the free curve processing in LinuxCNC system, and shows a good curve processing effect in the preview screen.