Abstract: In order to clarify the productive performance of straw mulch on soybean in saline soils, a comparative method was used to study its effect on water retention, plant rise and weed community characteristics in saline soils under straw mulch and fungicide seed dressing treatments. The results showed that the water content of JM（fungicide seed dressing and straw mulch） and KM（straw mulch） treatments was higher than CK by 1.18% and 1.06%, with significant differences（P＜0.05）. Straw mulching reduced evaporation of water from the soil and increased water content, while fungicide seed dressing had little effect on it. KM treatment increased their plant height at different times（P＜0.05） and J0（fungicide seed dressing） and JM treatments had no significant effect on plant height. The different treatments had little effect on the SPAD value and N content of the leaves of soybean plants, but had an effect on their above-ground dry weight, fresh weight and dry matter accumulation, especially at the later stages（7.22-8.15） when the JM and KM treatments accumulated the most dry matter, 0.52 and 0.56 g, respectively. In addition, weed species and densities were lower in the JM(78.94 plants·m^-2) and KM(147.37 plants·m^-2) treatments than in the CK(231.58 plants· m^-2) and J0(173.68 plants·m^-2) treatments. The KM treatment had the highest total weed biomass with an average of 82.76 g·m^-2. In summary, the grass slurry mulch had a water retention effect and promoted plant growth, and the grass slurry mulch with fungicide application reduced weed growth. This study provides a theoretical basis for the promotion of degradable plastic film cultivation technology.