In this paper we present a C1 interpolation scheme on a triangle. The interpolant assumes given values and one order derivatives at the vertices of the triangle.It is made up of partial interpolants blended with corresponding weight functions.Any partial interpolant is a piecewise cubics defined on a split of the triangle, while the weight function is just the respective barycentric coordinate. Hence the interpolant can be regarded as a piecewise quartic. We device a simple algorithm for the evaluation of the interpolant. It’s easy to represent the interpolant with B-net method. We also depict the Franke’s function and its interpolant, the illustration of which shows good visual effect of the scheme.