"Open PDF" is a PDF-based e-book, support the use of keywords to search PDF format e-books, in addition to support for search also supports indexing out of the download address, the user can directly download the search e-book, but to respect the publisher and author's authorization, personal learning to use.

"Open PDF" search engine is based on Google's custom search function optimization, in addition to search for e-books, but also improve the PDF viewer and PDF toolbar, users can search for e-book url links into the viewer to read.