In order to explore effects of tillage on dynamics of soil water and salt in saline-alkali soils in the Hetao Irrigation District in Inner Mongolia, a micro-plot field experiment, designed to have four treatments, i.e. Treatment T (tillage), Treatment P (plastic mulching), Treatment S (deep burial of straw) and Treatment P S (plastic mulching plus straw burial), was conducted over a whole sunflower growing period. Results show that Treatment P S not only significantly enhanced water storage capacity of the 0~40 cm soil layer, but also continuously preserve soil moisture. Soil water content of the 0~40 cm soil layer was 5.13%, 3.49% and 1.99% higher in Treatment P S than in Treatments T, P and S before sowing, respectively. Compared to Treatment T, P and S, Treatment P S increased water content of the soil layer by 5.01%, 5.87% and 2.70%, respectively, at the early growing period, and by 7.53%, 11.02% and 6.16%, respectively, at the medium growing period. Moreover, Treatment P S displayed significant long-term effect of suppressing and controlling soil salt in the soil layer. Soil salt content was 18.37%, 20.33% and 1.90% lower in Treatment P S than Treatment T, P and S before sowing, respectively, 45.46%, 37.63% and 39.67% lower in the early growing period, 17.89%, 29.77% and 37.22% lower in the middle growing period, and 14.46%, 13.90% and 19.88% in the later growing period, respectively. In addition, Treatment P S significantly reduced salt accumulation per unit volume of soil, showing a significant effect of desalinizing the soil, particularly the plough layer. The above findings suggest that Treatment P S is an optimal option to regulate and optimize the distribution of soil water and salt, and create a suitable soil environment for better growing of sunflower.