样条是在二十世纪初经常用于图样设计的一种富有弹性的细长条，多个样条互相弯曲链接后沿其边缘画出的曲线就是三次样条曲线，而[a,b]区间上给定n+1个节点的三次样条插值函数一般满足三个条件：1.在每个子区间上，其插值函数都是三次多项式；2.节点上的插值函数值等于其函数值；3.在区间[a,b]上，插值函数的二阶导数连续。-Splines are often used in the early twentieth century elongated strip of a flexible design drawings, a plurality of splines each link its edges bent curve is drawn along the cubic spline curve, and [a, b] given the range of n+ cubic spline interpolation function a node generally meet three conditions: 1 in each sub-section, which is a cubic polynomial interpolation function　2 interpolation function on a node is equal to its function value . 3. In the interval [a, b], the second derivative of the number of continuous interpolation function.