All you need is Gmail account and Facebook account and Google Chrome Browser.
If you don’t have Google Chrome browser download it from here.
Lets see how to import your Facebook friends to your new Google+ account.
First Download and install ‘Facebook Friend Exporter’ Extension for Google Chrome from Chrome Web Store. This extension will allow users to get friends information like Name, Emails, Phone Numbers, Screen names, Website, Address and Birthdays.
After installing Go to Gmail and Facebook.com and login your account. Now you can see Extra option in the Above Blue bar like ‘EXPORT FRIENDS’ near Home button of the Facebook site.
Click that ‘Export Friends‘. It will ask to redirect to Friends page. Click ‘Redirect Now’.
Before the Facebook Friend Exporter Extension starts it will ask for accepting Terms of services. Check the box and click ‘Lets Get Started’.
The Facebook Friend Exporter will load all your friends contact details from facebook and after that Click’ Lets Start’
It will start Processing of all your Facebook friend’s Contact details. It will take minutes depending upon the number of contacts in Facebook.
After the Full process is over. It will ask two options to save the Contacts One is Gmail Contacts another one is CSV File.
Click GMAIL Logo to export the contact to your Gmail Account which you are using for Google+ profile. It will redirect you to give permission to Grant Access to Google Contacts.
Click ‘Grant Access’ and now all contacts are exported to gmail from facebook. Go to Gmail and Check your Contacts. You will see New Contact Group named ‘Imported from Facebook’ which contains all your facebook friends Contacts.
Now Just go to Google+ and Start adding your facebook friends from your gmail Contacts. or Even you can Save the contacts in CSV file.Video Tutorial:
Source: How to import your Facebook friends in Google+