The medium and heavy saline soils in the Yellow River Delta are important reserved cultivable resources in China, exploring the laws of soil water and salt transportation is significant to use these resources effectively, but the relative study is still less, especially the heavy saline soil. In this paper, cotton was planted in medium saline soil (3.10-3.90 g/kg) and heavy saline soil (4.60-5.70 g/kg) and irrigated with leached brackish water (salt concentration is 2 g/L). It was found that leached brackish water made the distribution of soil salt more uniformly in soil profile. Mulch film improved the absorption and utilization of soil water under the film, the main water-consuming layer was 0-40 cm in medium saline soil in cotton seedling and bud stages, while was 0-30 cm in heavy saline soil, water in deep layers (60-100 cm) was consumed due to crop growth in the later stage, and water absorption in deep layer was larger in medium saline soil than in heavy saline soil. Salt fluctuated within 0.80-2.00 g/kg and 2.00-5.60 g/kg in medium and heavy saline soil profiles, respectively. Soil salt content was lower inside mulch film than outside mulch film. The average desalination rate was 62.40% for medium saline soil and 55.83% for heavy saline soil in the harvest period. Cotton yield was 2 129.76 kg/hm² for medium saline soil and 823.66 kg/hm² for heavy saline soil. In conclusion, mulch film changes soil water and salt transportation in saline soils, mulch film can reduce water consumption, and medium saline soil showed better than heavy saline soil.