TiO2 nanoparticles doped with 2.0 at.% Sc and 2.0 at.% V calcinated at temperatures of 500-800 degrees 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 degrees C and then rapidly accelerated the anatase-to-rutile phase transition above 600 degrees C. However, the anatase-to-rutile phase transition is significantly inhibited by Sc V codoping until 750 degrees C. The M, H and A pattern evolutions of the average crystallite size of rutile with calcination temperature are found and two models are proposed for the findings. (C) 2016 Elsevier B.V. All rights reserved.