New seating, greenery, a new zebra crossing at Fore Street and improved pedestrian crossings throughout Trelowarren Street will be added as part of the scheme.
It will also include cycle parking, enhanced lighting, CCTV and extending on-street free parking at the top of Trelowarren Street from 30 minutes to one hour.
Works will continue through into the spring, with plans being developed to ensure the road is clear and open for Trevithick Day on 26 April.
Remaining works are due to be completed by the end of May.