TiO2 nanoparticles doped with 2.0 at.% Sc and 2.0 at.% V calcinated at temperatures of 500–800 °C were investigated by XRD technique. Results show that Sc doping promote the anatase-to-rutile phase transition compared to the pure TiO2, while V doping inhibit the anatase-to-rutile phase transition below 600 °C and then rapidly accelerated the anatase-to-rutile phase transition above 600 °C. However, the anatase-to-rutile phase transition is significantly inhibited by Scsingle bondV codoping until 750 °C. The M, И and Λ pattern evolutions of the average crystallite size of rutile with calcination temperature are found and two models are proposed for the findings.