XML has become the de facto standards for data representation and exchange on Web applications, such as digital library, Web service, and electronic business, etc. Indexing technique is still significant for efficient XML data processing. This paper discusses the actualities of the recent researches on XML indexing. It classifies the techniques into two categories, node-record-style index with three subcategories, and structural-summary-style index. It analyzes the virtue and deficiency of the related schemes based on the considerations for query processing efficiency and data modification supporting. And hereby it proposes three issues for future XML indexing researches, including internal structure retrieval, multi-dimensional processing on node paths, efficient modification-validating support and the index amalgamation for satisfying both querying and IR on XML data.