Jijing 105, a salt tolerant rice variety, and Ningjing 47, a salt sensitive rice variety, were used as experimental materials to compare the dynamic changes of grain filling rate, grain weight gain and panicle traits of the two rice varieties under three soil stress treatments with different salt concentrations. The results showed that under the aggravation of relative saline-alkali stress, the filling rate of strong grains in the two paddy varieties slowed down,the time to start filling was earlier, the time to reach the filling peak was shortened, and the weight gain of strong grains decreased. With the aggravation of saline-alkali stress, the time to start filling of weak grains in the two paddy varieties was delayed. The weight gain of strong grains in both paddy varieties was significantly higher than that of weak grains, and Jijing 105 reached the peak of dry matter accumulation before Ningjing 47. Under different saline-alkali stress, the panicle traits of the two paddy varieties were obviously inhibited by saline-alkali stress. The primary branch and stem traits were more stable than the secondary branch and stem traits, and the change was not obvious under saline-alkali stress. The reduction of panicle grain weight of the two paddy varieties was jointly affected by the reduction of 1 000-grain weight and number of branches and stems. Paddy yield and yield components decreased under different gradient saline-alkali stress compared with the control, and the reduction range was in direct proportion to soil saline-alkali stress. The reduction of paddy yield was mainly manifested in the reduction of branch number and 1 000-grain weight.