The money is being used to replace and extend a former caddie pavilion, near the first tee at the Old Course, and turn it into a waiting area for golfers.
The trust, which maintains seven courses, said the development would offer better toilets, a bag-drop facility and an information point to players.
A new caddie pavilion is being built while fencing, landscaping and footpaths are also being updated. The trust hopes to have the work completed by the end of April.
In addition the money, being provided by Royal Bank of Scotland, is being used to develop the trust's clothing and accessory brand Tom Morris International. Since launching last year, the brand, inspired by the four-time Open champion, has secured listings in Harrods as well as at golf clubs such as Pebble Beach and The Congressional in the US and The Els Club in the United Arab Emirates.
Euan MacGregor, the trust's finance director, said: "Through close co-operation between the bank and ourselves, the facilities were put in place quickly and efficiently to meet our needs."