A viscoplastic Ti6Al4V sheet annealing model is built by means of the MSC.marc software with the assumption and simplification of initial residual stress, to study the annealing distortion feature of the titanium alloy during annealing process. The effect of different annealing temperatures (550, 580, 600, 620, 650 ℃) on the annealing distortion is analyzed and the simulation is verified by the annealing experiments. The results show that, the inital residual stresses, which result in creep strain and elastic strain under the influence of creep, change strain distribution to the state of bending sheet and force the sheet to bend, are the fundamental reason of distortion. The increase of annealing temperature, along with the strengthening of creep effect, leads to the rise of annealing distortion, yet with no obvious effect on the variation trend of the stress and strain with respect to time. Moreover, the experimental results verify the reliability of the numerical simulation.