Ex-England captain Vaughan says the demands of the job, coupled with England's good form, make it unlikely Bell can ever get back in the squad.
Bell, 33, has replaced Varun Chopra as captain of the county side but still harbours England ambitions.
"I really don't see how Ian Bell at this stage of his career will get back in the side," Vaughan said.
"I think he'll struggle. When you see someone take over a county captaincy it's almost the final bow of a career," he told BBC Radio 5 live's Tuffers and Vaughan Cricket Show.
"I might be proven wrong because of the amount of runs he'll possibly score for Warwickshire . But when you get the opportunity to captain your county side, it's such a big job, a day in day out job."
Bell, who has played 118 Tests for England, was dropped for the current tour of South Africa after a poor run of form.
He said: "I know as much as anyone my last 10 Test matches weren't good enough. I was very short of runs so I'm not going to sit here and say I didn't deserve to be dropped.
"For me now it's about dusting myself off, getting back to doing what I do and that's scoring runs and getting stuck into Warwickshire."
England play the fourth and final Test against South Africa on Friday with the series already won.
Former England spinner Phil Tufnell said: "This England side now are just moving forward at such a pace, everyone who's coming in now is contributing massively and there's such a buzz about it, we haven't really thought about Ian Bell or him not being there.
"He's got a tough task. He will go back to Warwickshire and will score a mountain of runs because he's a class player but is there any room for him? Only time will tell."
Ian Bell's Test career is probably over following his decision to captain Warwickshire, Michael Vaughan believes.