The club has obtained a Section 106 planning order which states that the club will move into their new ground at Silver Bow on the outskirts of the city by 26 July, 2017.
"All the talking is finished," Truro chairman Peter Masters told BBC Sport.
"The diggers will go in in October this year, the building will commence in October or possibly before."
The agreement is similar to the one that the developers of the rival Stadium for Cornwall are waiting to be granted so they can begin developing their 10,000-seat ground for rugby union club Cornish Pirates.
Both grounds were granted planning permission at the end of July 2015, but had to get approval from the Department of Local Government and the Section 106 order before going ahead.
National League South side Truro had planned to share Torquay United's Plainmoor ground next season, but last month decided to stay at Treyew Road for one final season.
Once the new stadium is built, a retail park will be constructed on the Treyew Road site.
The new ground will meet the minimum grade 'A' standards, with a capacity for 4,000 fans and the potential for that to be increased to 5,000, making it suitable for the highest level of non-league football.
It will also have a synthetic 3G surface and conference facilities.
Masters and fellow businessman Philip Perryman took over the club in December 2012 when it was on the verge of liquidation, having gone into administration earlier that year.
After suffering relegation from what was then the Conference South, the club were promoted back to the second tier of non-league football last year when they won the Southern Premier League play-offs.
"If you think where we've come from, from £4.5m in debt and the ground being sold to a third party and relegation, we've turned it around," added Masters.
"We'll have a new stadium, which the football club will own. Coupled with it we got promotion last season and hopefully we'll make the play-offs this season, all while the club is debt free."
Work on Truro City's new stadium will start in October after the final legal document needed was signed.