Abstract: Shallow saline groundwater is expected to alleviate the shortage of freshwater resources in the Hebei Low Plain, China. However, using saline water for irrigation can increase soil salinity, thereby to pose some negative impacts on soil environment and crop growth. It is necessary to understand how salinity affects a crop, to find an acceptable range of salinity level for plants. In this study, a long-term furrow irrigation experiment with saline water for cotton (since 2006) was conducted to investigate the distribution of soil water-salt and response of cotton growth in the 10th year (in 2015), as well the variation of soil salt and yield of seed cotton over the years (2006 to 2015) at the Hengshui Experimental Station, China, in order to ensure sustainable and efficient use of saline water resources. Five salinity levels of irrigation water were tested: 2 (T1), 4 (T2), 6 (T3), 8 (T4), and 10 g/L (T5), and fresh groundwater (1 g/L) was used as control treatment (CK). The salinity level from T1 to T5 was formed by mixing sea salt into the freshwater. Irrigation water was supplied when the moisture content of soil was lower than 65% of the field capacity at each irrigation quota of 37.5 mm during cotton growing period. The results showed that the salt content in the soil layer of 0-100 cm increased with increasing salinity of irrigation water from 2006 to 2015, indicating a fluctuation with the precipitation and irrigation amount during the interannual period. In the treatment with the salinity of irrigation water, ≤4 g/L, there was no much increase in the soil salt content after cotton harvest in 2015, compared with the initial value in 2006. During the cotton growing period in 2015, the soil moisture in the furrow was higher than that in the ridge, while the soil moisture in the main root layer (0-40 cm) was higher in the treatment with the salinity of irrigation water, ≥6 g/L than that in CK. The soil salt content increased as the increase in the salinity of irrigation water, whereas increased first and then decreased with the advance of cotton growth. There was a trend of moving to the ridge and deep layer in the furrow of cotton field during furrow irrigation. There was no soil salt that accumulated in the main root layer after harvest, compared with that before cotton sowing. Saline water irrigation had a certain inhibitory effect on cotton growth. Lower salinity levels of irrigation water generally had few negative effects on cotton seedling rate, plant height and leaf area index (LAI), but the growth indicators of cotton were inhibited significantly when water salinity reached a certain limit. Compared with CK, the seedling rate and LAI significantly decreased when the salinity of irrigation water reached 6 g/L, where the threshold for the plant height was 8 g/L. There was no significant difference in the five quality indexes (upper half mean length, fiber uniformity, micronaire value, fiber strength and fiber elongation) among treatments, indicating furrow irrigation with saline water has little effect on the fiber quality of cotton. The yield of seed cotton in saline water treatments from 2006 to 2015 did not decrease gradually, but showing a large year-to-year fluctuation as the increased in irrigation over the years. There was an inconsistent state in the annual variation between cotton yield and soil salinity. Compared with CK, the cotton yield in the treatments of 2 g/L and 4 g/L showed no significant difference, but a significant decrease when the salinity of irrigation water beyond 6 g/L. The finding demonstrated that the critical salinity threshold of irrigation water can be set as 4 g/L for furrow-irrigated cotton.