Keith Justyn Meyers, who grew cannabis with a street value of around £85,000 in a factory on the outskirts of Penryn has been sent to prison.
The 44-year-old was convicted of production of the drug at Truro Crown Court.
Officers discovered a large cannabis grow in the factory unit in April 2011.
There were 346 plants at various stages of growth and the sophisticated set up consisted of lights, timers, ventilation and other equipment.
In summing up the judge, Mrs Justice Sharp said 'You lied in your interview and you have lied here.
"I am going to sentence you on the basis that you played a significant role in a commercial enterprise that had a value in excess of £85,000 and had a potential annual value based on three crops per year in excess of £257,00."
He was sentenced to four years and three months imprisonment.