A modified PEBI grid generation method with frontal approach is proposed,which is used to investigate reservoir modeling.Validity of the PEBI grid generation method is shown by comparing results of a self-developed reservoir simulator with that of a software CMG.A synthetic case with irregular boundary is investigated.It shows that PEBI grids reduce influence of grid orientation compared with conventional Cartesian grids.It is favorable to describe complex reservoir boundaries accurately and to implant internal constraints such as vertical well,fault in PEBI grid generation method.