Abstract: Abstract: For understanding the interaction effect of salinity and nitrogen on sunflower growth, complete block design experiments were conducted in Hetao Irrigation District of China, and the observation index included sunflower emergency rate, plant height, leaf area, above-ground dry weights, nitrogen uptake, and yield. To be more specific, 14 days after sowing, we observed the number of sunflower seedlings daily, and their emergence rate was calculated by dividing the number of seedlings 14 days after sowing by the total seeds of sunflowers. Furthermore, the leaf area was measured by a portable leaf area meter (YMJ-C, TuoPu, China), and plant height was measured by tape. After the sunflowers were harvested, sunflower seeds were weighed after air-drying (moisture <8%), and then sieved to remove debris; two uniform plants from each lysimeter were manually uprooted at maturity for nitrogen uptake analysis and determination of biological yield. These plants were partitioned into flower disks, stems, leaves, seeds, and roots, were weighed after drying at 70℃ to a constant weight, and the biological yield of each component was recorded. In order to determine nitrogen uptake, samples of each plant part were grinded and screened through a 0.5 mm sieve. Total nitrogen concentration was determined by the micro-Kjeldahl method, and the ratio between seed yield and nitrogen application was selected as the evaluation indictor for nitrogen use efficiency of each micro-plot. The experimental results indicated that soil salinity significantly affects sunflower growth, and that the soil salinity level of S4( >1%) could reduce 72.0% emergency rate, 40.0% plant height, 58.5% leaf area, and 76.4% yield related to the S1(0-0.25%) salinity level. Furthermore, sunflower emergence has a negative linear relationship with soil salinity in different nitrogen application rates. A nitrogen fertilizer application could alleviate the adverse effects of salinity on sunflower growth to some extent. To be more specific, at the S3 salinity level (0.5%-1.0%), increasing the nitrogen application rate from N1(90 kg/hm2) to N3(180 kg/hm2) could increase the emergence rate, plant height, leaf area, dry matter amount, and seed yield to 16.7%, 35.6%, 39.1%, 69.9%, and 80.0% respectively. Furthermore, when the salinity level was above 1.0%, these 5 indicators increased 45.4%, 20.5%, 47.4%, 42.7%, and 76.2% respectively. However, this relationship was not obvious when the soil salt content was smaller than 0.5%. In addition, although sunflower nitrogen uptake increased with nitrogen application, the nitrogen use efficiency (NUaE) was also affected by the soil salinity level. More exactly, when the soil salt content was smaller than 0.5%, the NUaE decreased with the nitrogen application, and the opposite phenomenon occurred when the soil salt content was larger than 0.5%. Moreover, taking economic profits, environment production, and irrigation schedule into consideration, we suggested the optimal nitrogen application rate for sunflower growth in the Hetao Irrigation District was 135 kg/hm2.