In order to realize heterogeneous computing, one must firstly find Out the parallelism charac-teristic for a segment of program. But the existing theory of paratlel processing is not soph Lsticated, and prevents paralte computing from becoming the mainstream in computer applkat Lons Therefore, it is necessary to achieve breakthroughin schemes of research Inthis paper, a novel approachto data depen-dence analysis, based array element graph, is proposed. By meare of graph theory and algebra abstract, the authors infer and prove what parallelism characteristic types O single nested loop program have The paper also establmhes a foundation for further research in such area.