Derek Hole, 83, from Kingston Seymour, Clevedon was the sole director of Briar Building Ltd.
He submitted VAT returns, claiming refunds for the purchase of building supplies totalling £644,579.14 between January 2012 and September 2017.
Hole claimed the company was constructing new build residential properties, which are generally zero-rated for VAT purposes.
Investigations discovered the purchases were fictitious and the claims were made up to illegally receive VAT repayments. Hole was arrested in March 2018.
Richard Wilkinson, Assistant Director, Fraud Investigation Service, HMRC, said: “Hole lied so he could claim money he wasn’t entitled to.
“He manipulated a system that exists for the benefit of legitimate companies, individuals and charities with the sole purpose of cynically lining his own pockets.
“He knew he was breaking the law, yet chose to overlook it for the opportunity of making what he wrongly assumed would be easy money, at the expense of the taxpayer.”
Hole was sentenced yesterday to two years and ten months in prison when he appeared at Bristol Crown Court.