The 28-year-old defeated Turkey's Hatice Kubra IIgum 20-5 in Bulgaria’s capital, Sofia.
Jones had comfortable victories over Belgium’s Raheleh Asemani, Finland’s Suvi Mikkonen and Romania’s Alexandra Ge Rache on her way to the final.
The Great Britain star is working to become the first Team GB woman to win three individual gold medals at three different Olympic Games, after winning gold at both London 2012 and Rio 2016.
Jones is part of a 15-strong British squad competing at the European Championships, which will run until Sunday 11 April.
The competition is the first major event of 2021 for many athletes, giving them a chance to gauge their fitness and form, with the Tokyo 2020 Olympics less than four months away and the World Championships in October.
Sofia is also set to host the European qualifier for the Tokyo 2020 Olympics on 7 and 8 May.