Resource discovery is a fundamental problem in grid systems. Original approaches to provide grid resource discovery services are either centralized or hierarchical and proved to be inefficient when the scale of grid systems rapidly increases. A P2P network is a distributed system with the attributes of dynamicity and scalability. P2P systems have the same goal as grid systems: to share and exchange various resources. With their development, P2P systems and grid systems can be combined into a new system which has their attributes. In this paper, a novel hierarchical P2P based grid model based on the existing grid resource discovery models is discussed. In our model, Chord and Gnutella are selected as the typical protocols to form the virtual P2P layer. Through the experiment results, we argue that the 3C-2G model performs better than the other models in resource discovery among grids oriented to the same application field.