The Dutch rider made her move from four kilometres out, quickly opening up a five second gap on world number one Emma Johansson and Rossella Ratto.
And although Johansson and Ratto worked together to try and claw Vos back, their attempts were to no avail as they finished second and third respectively.
The Italian team, with double world champion Giorgia Bronzini, were looking to isolate Vos, but she never looked troubled, having Anna van der Breggen to thank after her team mate protected her all day.
Vos now has 13 cycling gold medals from world championships or Olympic Games.
It was also the 26-year-old Vos's eighth consecutive world road race podium after she won the title in 2006 before taking second place five years in a row.
Great Britain’s Lizzie Armitsead fell away from the lead group and finished outside the top 10.
1. Marianne Vos (Netherlands / Netherlands) 3:44:00"
2. Emma Johansson (Sweden / Sweden) +15"
3. Rossella Ratto (Italy / Italy)
4. Anna van der Breggen (Netherlands / Netherlands) +33"
5. Evelyn Stevens (U.S. / U.S.) +46"
6. Linda Villumsen (New Zealand / New Zealand) +50"
7. Tatiana Guderzo (Italy / Italy) +52"
8. Elisa Longo Borghini (Italy / Italy)
9. Tiffany Cromwell (Australia / Australia) +1:40"
10. Tatiana Antoshina (Russia / Russia)