To further study the effect of different crop rotation patterns on the productivity of oilseed flax. In this study, the “Jinya No. 10” flax cultivar was used as the object, and a DSSAT model was constructed using 2017-2018 data to simulate the field trials (4-year rotation cycle) during the 30 years from 1994. The experiments were designed with six different crop rotation patterns including the following: flax→flax→flax→flax[(F)FFF], flax→wheat→maize→flax[(F)WMF], flax→maize→flax→wheat[(F)MFW], flax→flax→wheat→maize[(F)FWM], flax→wheat→flax→maize [(F)WFM], flax→wheat→maize→wheat[(F)WMW]. We investigated the effects of crop stubble, planting frequency of oilseed flax, years between plantings of oilseed flax, and years of continuous cropping on grain yield, aboveground biomass, and water use efficiency (WUE) in a semi-arid agricultural area. The results of the study showed that: (1) In the model calibration and validation, the RMSE of yield was 213.67 kg ha−1−217.43 kg ha−1, the RRMSE was 9.76%-10.79%; the RMSE of aboveground biomass was 796.24 kg ha−1−1527.81kg ha−1, the RRMSE was 13.46%-22.71%. The growing period of the cultivar was 95-97 d, indicating that the DSSAT model can simulate the productivity index of oilseed flax well. (2) Oilseed flax yield rotation than continuous mode significantly increased, the increase in 53.43%-54.28%, wheat, and maize stubble both significantly increased oilseed flax yield, compared with oilseed flax stubble increased by 31.04%, 31.95%. 25% oilseed flax frequency and 50% oilseed flax frequency than 100% oilseed flax planting frequency was significantly increased by 54.28% and 53.79%. The increase in grain yield of oilseed flax in the planting interval years was shown as 2a (32.97%) > 3a (31.51%) > 1a (30.84%). (3) The aboveground biomass of oilseed flax in the crop rotation compared to the continuous cropping pattern had a significant increase in the increase ranged from 60.49% to 100.31%. Wheat and maize stubble significantly increased the aboveground biomass of oilseed flax, compared with oilseed flax stubble increased by 25.67% and 22.56%. 25% oilseed flax frequency and 50% oilseed flax frequency than 100% oilseed flax planting frequency significantly increased by 92.02% and 72.81%. Oilseed flax aboveground biomass production in the planting intervals between the years of the increase in the performance of the 3a (39.8%) > 2a (28.99%) > 1a (19.45%). (4) The WUE of rotation compared to the continuous cropping mode increased between 45.78% and 58.54% for flax. The presence of wheat and maize stubble significantly increased the WUE of oilseed flax, compared to stubble of oilseed flax, which increased by 29.32% and 32.41%. 25% flax frequency and 50% flax frequency than 100% oilseed flax planting frequency significantly increased by 45.77% and 59.73%. Compared to the interval year 0a, the specific increase in WUE showed 2a (33.03%) > 1a (31.37%) > 3a (26.06%). Therefore, the continuous cultivation of oilseed flax will reduce productivity, should choose to rotate farming methods, replace different stubble, reduce the frequency of oilseed flax planting, and extend the interval between years of oilseed flax planting, and flax→wheat→maize→wheat is a suitable crop rotation mode in the northwestern dry zone.
