Minor components can affect the hydration activity of dicalcium silicates (C2S) through the modification of its phase composition.In this paper,the influences of BaO,SO3 and MgO on burnability and phase composition of belite have been investigated.The results showed that SO3 could significantly decrease the f-CaO content of C2S due to the substitution of [SiO4]4- by [SO4]2-,accelerate the formation of C2S and effectively stabilize β-C2S.Different from SO3,BaO and MgO would increase the f-CaO content due to the substitution of Ca2+ by Ba2+ or Mg2+.