In the paper, an averaging principle problem of stochastic McKean-Vlasov equations with slow and fast time-scale is considered. Firstly, existence and uniqueness of the strong solutions of stochastic McKean-Vlasov equations with two time-scale is proved by using the Picard iteration. Secondly, we show that there exists an exponential convergence to the invariant measure for solutions of the fast equation of stochastic McKean-Vlasov equations with slow and fast time-scale. Finally, strong averaging principle for two-time-scale stochastic McKean-Vlasov equations is investigated.