A PDE model is proposed in this paper to construct the information potential fields in sensornets. A parabolic equation is introduced to determine the field and the finite differential method is used to salve it. The solution preserves major nodes'' features which are advantageous to most applications of sensornets. More than one piece of information potentials fields can be intergraded together naturally due to the sound property of the PDEs. Efficiency and stability of our method are verified by several numerical examples.