You can refer to the webpage help: http://helpx.adobe.com/lightroom/help/import-iphoto.html
To import photos from iPhoto into Lightroom, first you have to help Lightroom find the original photos, which are hidden in a package file. Then, you can copy or add the photos to a Lightroom catalog just like you would import any other photos from a folder on your computer.
Note: These instructions are for iPhoto '11 version 9.2.
A Finder window opens that shows the contents of the package file. The Masters folder contains all of the photos that are in iPhoto. However, Lightroom cannot access this folder.
Lightroom can see this folder.
The import window opens, with your iPhoto files selected in the preview area. By default, Lightroom wants to Add these photos to your catalog. Select Copy or Move, if preferred, and specify the destination folder and other options in the panels on the right side of the import window.