Use the print to file option to:
You can create multiple-page PDF files from Illustrator CS and earlier by:
You can use the Create Multi-page PDF From Page Tiles option in the PDF save dialog box to create multiple-page PDF files directly from Illustrator CS2- CS5. You can also print separations to file and then distill the file in Acrobat Distiller, creating a multiple-page PDF file in which each page represents a different printing plate.
The Page Tiling options in Illustrator were not specifically created for this workflow, and results vary according to the version of Illustrator you use and the operating system in which you use it.
Illustrator CS5 and earlier
When you print to file using multiple tiled pages, Illustrator creates only one PostScript file that contains only a single tile or page. Usually, Illustrator includes the last tile or page in the Illustrator document in the PostScript file. For example, if you print a six-page tiled Illustrator document to file, Illustrator includes only the sixth and last tile in the PostScript file.
When you print to file using separations, Illustrator creates one PostScript file. When you distill this file, Acrobat Distiller creates a multiple-page PDF file. The number of pages depends on how many plates you printed.
When you print to file using multiple tiled pages or separations, Illustrator creates one PostScript file. When you distill this file, Acrobat Distiller creates a multiple-page PDF file. The number of pages depends on the number of tiles in the document (for files set up with page tiling options), or on how many plates you are printing (for files from which you are printing separations).