The wave packet dynamics of I2- anions is studied by using the time-dependent wave packet method. Two conclusious can be drawn from the calculations.First,the period of the total photoelectron signal oscillating with the propagation of delay time is about 750 fs.Second,the photoionization of I2- anions begin at the time 600 fs,and the time needed for the population of the electronic state of I2 neutral molecule to reach the maximum becomes shorter with the increasing delay time.