Guthrie, who scored 12 goals last season as the National League club lost to Grimsby in the promotion final at Wembley, has signed a two-year deal.
The Jersey-born 23-year-old previously played for Accrington Stanley, Southport, Bath City and Welling.
Meanwhile, U's defenders Tom Eastman, 24, and Jamie Harney, 20, have signed new one-year contracts.
Former Ipswich trainee Eastman has made 197 appearances since joining Colchester in 2011.
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League Two side Colchester United have signed Forest Green Rovers forward Kurtis Guthrie for an undisclosed fee.