The Dutch cyclist led from start to finish along the 21.8km course and created a 24.1 second gap with No 2 Linda Villumsen.
Ellen van Dijk of the Netherlands dominated the women's time trial to win her second gold medal at this year's road cycling world championships on Tuesday in Florence, Italy.
The 26-year-old time trial specialist, who was the pre-race favorite, posted a time of 27 minutes, 48.18 seconds, beating Linda Villumsen of New Zealand by 24.10 seconds. Carmen Small of the United States was third, 28.74 seconds behind Van Dijk.
The powerful Van Dijk, who picked up gold in the team time trial on the opening day on Sunday, was one of the last to start. The 26-year-old led from start to finish along the 21.8km course.
Earlier, Igor Decraene of Belgium won the junior time trial, beating favorite Mathias Krigbaum of Denmark. – Sapa-AP