Abstract: A new spline curve is presented which interpolates given points and tangent directions with piecewise involute of circle.Each pair of adjacent points with given tangent directions are interpolated in most cases by two segments of involute of circle.Since involute of circle has many good properties such as convexity,inverse variation of curvature with arc length,the spline is advantageous for shape control,and could act as an extension of circular arc spline.