In order to accurately obtain the distribution information of soil potassium in the soil profile, and know well the regional migration of potassium and the need of reasonable precision fertilization, 134 soil profile (0-100 cm) samples were collected. Based on the sampling data, the distribution characteristics of soil available potassium in soil profiles of the western part of Chengdu Plain were studied through classical statistical and geostatistical methods, and the effects of parent material, soil type and land use on the available potassium distribution were compared and analyzed. The results found that the soil available potassium content had certain regularity in the horizontal direction, and its high value was concentrated in the Chongzhou, Qionglai and Dayi areas, which were south parts of the Jinma River, while the low value appeared in the Dujiangyan-Pixian-Wenjiang area. The area of the low-value-area accounted for more than 50% of the study area, and the overall showed a significant downward trend from the southwest to the northeast. In the vertical direction, the content of soil available potassium decreased with the increasing of soil depth in the range of 0 to 100 cm, and the available potassium content in top soil was significantly higher than that in the lower soil layer (P<0.05). The amplitude of soil available potassium content (the difference between the maximum and the minimum) in the lower soil gradually decreased with the increasing of soil depth. The nugget coefficients of different soil layers within 0 to 100 cm were between 25% and 75%, showing moderate spatial autocorrelation, which were affected by structural and random factors. The spatial distribution of available potassium in surface soil was affected by soil parent material, soil type and land use pattern, and the explanatory ability of soil type was the highest, which was 1.97 and 2.58 times that of soil parent material and land use pattern, respectively. The spatial distribution of available potassium in lower layer soil was mainly affected by the parent material and land use pattern, and the impact extents both increased with the increasing of soil depth, however the influence of parent material was more significant. The results showed that the parent material and land use pattern were the main controlling factors, which affecting the profile distribution of soil available potassium in the study area.