The 31-year-old striker moves to Highbury after spending almost all of last season on loan at Championship outfit Blackpool.
After joining Palace from Brighton and Hove Albion last July, Dobbie made just one Premier League appearance prior to two loan spells with Blackpool, which saw him score four goals in 27 games.
A player with considerable appearance in the Football League, Dobbie will hope to guide Fleetwood to a solid finish in their first season in the third tier after the Lancashire side won promotion from League Two via the play-offs last term.
The arrival of Dobbie comes on the same day that Fleetwood signed young Newcastle United striker Adam Campbell on a 28-day loan.
Campbell, 19, made three senior appearances for Newcastle last term while also spending time on loan at Carlisle United and St Mirren.
Both players could make their debuts in Fleetwood's League One opener against Crewe Alexandra on Saturday.
