To explore the effects of different tillage methods and straw returning treatments on soil available potassium content and annual yield of rice under fixed point conditions，a long-term positioning experiments was conducted on the experimental field of Agricultural College of Yangzhou University from the autumn sowing in 2001 to summer sowing in 2021.A total of six treatments were set up in the experiments，including no-tillage and straw returning of rice and wheat continuously(NTS)，convention tillage of wheat and no-tillage of rice(RT1)，convention tillage of riceand no-tillage of wheat(RT2)，convention tillage and straw returning of rice and wheat continuously(CTS)，minimum tillage and straw reduce returning of riceand wheat continuously(MTS)，convention tillage and no straw reduce returning of rice and wheat continuously(CT).Soil available potassium content and rice yield under each treatment were measured after rice ripening every year.The results showed as follows:(1)Straw returning significantly increased soil available potassium content in topsoil layer，and compared with CT treatment，the average soil available potassium content under NTS，RT1，RT2，CTS and MTS treatments were increased by 9.28%，5.95%，7.10%，16.55% and 15.23%，respectively.(2)The effect of NTS treatment on soil surfacea vailable potassium content was higher than that of CT treatment by 14.16%.MTS treatment promoted the accumulation of available potassium in the middle soil layer，which was 18.42% higher than that of CT treatment.CTS treatment had a greater effect on the content of available potassium in the lower layer of soil，which was increased by 20.74%，compared with CT treatment.(3)Compared with CT treatment，rice yield of CTS and MTS treatments were increased by 4.48% and 5.07% onaverage，respectively，while rice yield of NTS treatment was decreased by 5.58%，compared with CT treatment.The combination of tillage and less tillage with straw returning hada positive effect on the accumulation of available potassium in the lower layer of soil in the middle stage，but the effect was not obvious in the early stage.(4)Except for NTS treatment，rice yield under other treatments was increased with the going by of time in different amplitude.(5)There was a significant positive correlation between available potassium content in the lower layer of soil and rice yield(Pearson correlation coefficient r=0.26).The above results showed that both minimum tillage and straw reduce returning in rice and wheat continuously(MTS)and convention tillage and straw returning in rice and wheat continuously(CTS)had the significant effect on the soil available potassium content and rice yield.From the perspective of labor saving，minimum tillage and straw reduce returning in rice and wheat continuously could be the most suitable tillage method in this area.In addition，the combination of different tillage methods and straw returning had cumulative effects on soil available potassium content for many years.