Paul Furlong scored his 200th career goal to end Barnet's relegation fears but keep Bournemouth in trouble.
Lee Bradbury headed against the bar for the visitors early on after Bees keeper Jake Cole was left stranded.
Jason Pearce's header was then cleared off the line as the Cherries dominated, but Furlong grabbed the only goal with a trademark header in the 51st minute.
Jeff Goulding also had a shot hacked off the line as Barnet clung on to guarantee League football next season.
Bournemouth remain four points above the drop zone, with four games remaining, after rivals Chester and Grimsby also lost.
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