In order to improve crop yield under drip irrigation with brackish water and to clarify the effects of different leaching time on desalination and increasing yield, a salt leaching was conducted at the jointing stage (T1), tasseling stage (T2) and filling stage (T3) respectively in the Jingbu saving water experiment station of the Hetao irrigation area, Inner Mongolia. With no leaching in the growth period as control (CK), a total of 4 treatments were carried out to study the effects of leaching at different growth stages on soil water and salt and crop yield under mulched drip irrigation with brackish water. The results showed that the soil water contents increased by 18.9% from 0-60 cm after leaching at different growth stages, and the soil water contents of 0-40 cm under T1, T2 and T3 were significantly higher than that of CK, which durations were 12, 25, 28 days respectively. After the salt leaching, the soil water storages and water consumptions increased by 20.92% and 21.52%, respectively. The average salt contents below mulch decreased by 78.0% after leaching, and the salt content decreased by 0.20, 0.36, 0.44 mS/cm after leaching at jointing and tasseling and filling stage respectively. After leaching, the desalination rates below mulch increased by 55.01% from 0-60 cm, and by 125.79% from 60-100 cm. The desalination rates beyond mulch after leaching was higher than that below mulch by 38.9% averagely. The salt leaching at the jointing stage significantly increased maize yield and its components, by 18.8% for yield, by 6.8%, 5.5% and 7.0% for spike length, ear width and grain number, respectively, and by 7.8% (P<0.05) for harvest index. The salt leaching at the tasseling stage increased yield by 8.1% (P<0.05), but the effect of leaching at the filling period was not significant (P>0.05). Therefore, the salt leaching at the jointing stage resulted in the less salt stress, under which crop yield could be increased obviously.