Evans won the gold medal with 60 points, finishing ahead of Denmark's Julie Leth (53) and the United States' Jennifer Valente (51). Evans' gold came after she won silver in the women's team pursuit earlier in this year's championships.
"It's not really sunk in yet. I'm full of adrenaline and excitement, but I'm delighted," Evans said after the race.
"I definitely felt like I had good legs and I had a really good gameplan going in, so I was quite confident."
In the men's elimination race, Italy's Elia Viviani retained his title as New Zealand's Corbin Strong took silver and Britain's Ethan Vernon won bronze.
Dutchman Harrie Lavreysen earned his second gold of this year's championships in the men's sprint, with Australians Matthew Richardson and Matthew Glaetzer grabbing silver and bronze respectively.
Germany's Lea Sophia Friedrich defended her world title in the women's Keirin as Japan's Mina Sato won silver and Steffie van der Peet of Netherlands took bronze.
France won the men's madison with Britain second and Belgium third.
