Based on a neutral barium cloud diffusion model, considering the oxidation and ionization loss of barium atoms, the early (t 100 s) evolution characeristics, morphologies, brightnesses and electronic density distributions of barium clouds released in the ionosphere are discussed in this paper. The numerical simulation results are presented for the early dynamics of barium clouds with different released masses (1, 10 kg), different release altitudes (250, 300 km), and different initial shape factors (1, 10).