Cadmium (Cd)-contamination of agricultural soils has raised a worldwide concern because of its high toxicity to plants; also it can be transferred via the food chains and accumulate in human bodies, resulting in many health problems such as itai-itai disease, liver damage, lung edema, and so on. Meanwhile, the application of potassium (K) fertilizers has a broad influence on the transportation and accumulation of Cd in soil-crop system. Therefore, a greenhouse pot experiment was conducted with in-situ Cd-contaminated soil to study the influence of different forms of K fertilizers (KCl, K₂SO₄, and KNO₃) on Cd accumulation in rice, wheat, and pakchoi as well as Cd fractions in soils. The results showed the Cd contents in all crops increased in the KCl treatments; it increased by 10.84%-172.77%, 17.09%-67.72%, 15.27%-41.22% in rice grains, wheat grains, and pakchoi shoots, respectively, when KCl dose increased from the lowest to the highest. Generally, in the K₂SO₄ treatment, the Cd contents in rice decreased greatly while those in wheat and pakchoi increased slightly. The supply of KNO₃ also led to an increase in the Cd contents in crops. In addition, KCl resulted in a significant increase in the NH₄NO₃ extractable Cd (NEX-Cd) content in paddy soil. However, there were no significant differences in NEX-Cd content between all the treatments in wheat soil or pakchoi soil no matter which forms or doses of K fertilizers were applied. Consequently, when K fertilizers are applied to in-situ Cd-contaminated soils, both forms and doses should be fully considered to mitigate the Cd accumulation in crops, especially the edible part. Hopefully, our manuscript can offer opinions to understand underlying mechanisms of Cd transportation in soil-crop system when soil was disturbed by potassium fertilizers.