Compress your Outlook PST file by using "Compact Now" feature of Microsoft Outlook. But, the size of your PST file is quite large so please don't take any risk with your important Outlook data files. I mean to say that you should go with any third party software. I would like to give you two better solution on the behalf of my personal experience. First is obviously Compress your PST file and the second one is PST Compact and Compress Tool.
Learn more info, here:- Compress Outlook PST Files.

 

The KDETools PST Splitter is the best way to compress the large PST files into small PST files. This tool easily split the PST files by date, size, year and folder. This software is very advanced features and it supported all the Version. This Software compress unlimited PST files.

More Details: Split PST Tool to Divide/Split Large Outlook PST File into Smaller Parts

 

If you are looking a tool that can Compress Outlook PST files then you can use this Outlook PST compress Tool will help you to compress and reduce Outlook PST file size. Compress PST Software is definitely a good choice that allows you to compress multiple files at a time without any loss of data and efforts of the users. The tool works on all Outlook editions without any disturbance.

 

Compress large-size PST data with the help of Softaken Compact PST Application has the ability to compress Outlook PST files by including and excluding the attachments. It supports removing the extra space and unused space. The application is extremely well designed to compact extra-large Outlook PST files to avoid any type of corruption and to save space in the hard drive of the system.