The Super League side confirmed it had bought the ground from its previous owners, the 88m group, on Thursday afternoon.
It comes after Wakefield Council loaned the club £3m to help complete the transaction, and the club are now expected to remain at the venue they've called home since the late 19th century.
Trinity chairman John Minards said completing the deal was a "great feeling".
"It's a big step forward for the club," he said. "Owning our own ground means we can control our own destiny and hopefully deliver the community stadium that we want."
"We're really grateful to the council for their support on this and to the 88m group as well.
"It's a historic day and I'd say it's the end of the beginning now."
Belle Vue has to be redeveloped to meet new standards for rugby grounds, but Mr Minards said the overall scale of improvements rested on extra cash.
He added: "It's too early to say exactly what we're going to do. We're aware of the minimum standards we have to reach, but how grand it will end up being is dependent on further investment.
"We're talking to a number of parties about that.
"But importantly, we want to deliver a stadium that the community will be able to use."
Trinity fans were left frustrated by a lack of progress towards a newly built community stadium on Newmarket Lane in Stanley, which was given planning permission in 2012.
But Mr Minards said he hoped supporters would be happy with the club staying at Belle Vue.
He added: "I think the fans have a lot of affection for Belle Vue. No-one knows for certain how long we've played here, but we think it's been since at least the 1880s. That means we're approaching 150 years here, which is special."
In a statement, Manni Hussain from the 88m group said: "We are delighted to have been able to reach this historic agreement with Wakefield Trinity and Wakefield Council.
"We have been working closely with both parties for some time, and now we are pleased that after so much uncertainty regarding the club’s future this deal has secured it.
"Let’s all look forward for this great club to prosper and wish them well for the seasons ahead."
The council's deputy leader, Denise Jeffery, who's been closely involved in negotiations, said: "The city of Wakefield is famous across the world because of Wakefield Trinity and we are delighted to have played a part in ensuring that the city’s only professional sports club is staying at its traditional home.
"We look forward to continue to work closely with the club as it develops the stadium."