A pot experiment was conducted to study the influence of different doses of potassium fertilizers (K₂SO₄ and KCl) on lettuce, Lactuca sativa, quality and soil under Cd stress. The results showed that application of proper dose of K₂SO₄ could increase the fresh mass of lettuce and decrease Cd content of lettuce shoots, while nitrate contents increased significantly and the nutrient quality decreased at the same time. KCl showed the opposite tendency. Soil available K increased with doses of K₂SO₄ and KCl increasing, and K₂SO₄ had no obvious influence on soil available N and P. At the application level of 400 mg·kg^-1, K₂SO₄ and KCl both decreased soil pH and increased soil DTPA-Cd contents. Basically, K₂SO₄ had better effects on decreasing shoot Cd contents of lettuce than KCl, while KCl had better effects on improving nutritional quality of lettuce than K₂SO₄ and a higher risk of increasing DTPA-Cd contents in soil than K₂SO₄ at the same time.