Villa went into the second leg holding a two-goal cushion from the first leg, with Martin O'Neill's side having won 3-1 in Bulgaria.
The opening stages at Villa Park gave the visitors some hope, as they started to find some rhythm in their passing without troubling the Villa defence.
However, Moustapha Salifou rifled a shot narrowly over 11 minutes in and Zat Knight threatened from a Nicky Shorey corner with just over 20 minutes played.
With 27 minutes on the clock Marlon Harewood gave Villa the lead on the evening, latching on to an Ashley Young pass to shrug off two defenders and finish coolly past keeper Todor Todorov.
Harewood went close to a second just past the half-hour mark and right on the stroke of half-time Knight headed over as Villa began to turn the screw.
Litex Lovech got some reward for their efforts early on in the second half, as Carlos Cuellar brought down Wellington da Silva in the area and Wilfred Niflore despatched the spot-kick past Brad Friedel.
Villa responded with Wayne Routledge having an effort parried by Todorov, before Harewood headed over following good work by Shorey and Ashley Young.
Eleven minutes from time Ashley Young found space in the area and seemed certain to restore Villa's lead, but his close-range effort came back off the upright with Todorov beaten.
However, the Midlanders had done their job and continued their fine start to the new season, both at home and in Europe.