This paper discusses a new partial differential equation model for resolution enhancement of image.This model adapts the prior information of piecewise continuity of image to construct a nonlinear diffusion model

which is used to smooth an enlarged image by nearest interpolation to reduce the blocky effect caused by enlargement

simultaneity

and interpolation condition is added into the iterated process to avoid a too smooth image.The algorithm is tested by three remote sensing images

all of the results show that the new model has higher peak signal to noise ratio and higher edge preserve index than the known methods.