The van was parked near a home north of Gardiner, which is north of Yellowstone National Park. The van's owner discovered the bear in the vehicle at about 11 p.m. Saturday.
The Livingston Enterprise reported a Park County sheriff's deputy and a Fish, Wildlife and Parks game warden tied a rope to the door handle, took cover and pulled the door open. The bear ran off.
The interior of the van was damaged.
Officials say the van is used to haul garbage and odors likely attracted the bear.