To select parent tobacco with combining abilities of high potassium content, the combining abilities of 6 flue-cured tobacco genotypes with high potassium efficiency at different potassium application levels were investigated by incomplete diallel cross method. The results showed that the GCA (general combining ability) variances of potassium content reached significantly or extremely significantly levels among genotypes in leaves from all stalk positions, except in lower leaves at high potassium level. The GCA effect was obviously different among genotypes. At the potassium application level of 120 kg/ha, GK8 showed better GCA effect of potassium contents in leaves from every stalk position in contrast with GK3 and GK9; at the application level of 360 kg/hm², GK2, GK7 and GK8 performed well contrasted with GK3, GK5 and GK9; at the application level of 600kg/hm2, GK2 and GK9 performed better than did GK7 and GK8. For the SCA effect of potassium content, the variance among the three application levels all reached extremely significant level. MsYunyan87×GK9 had a positive SCA effect of potassium content for leaves from every stalk position at different potassium application levels, followed by MsChangbohuang×GK3, MsChangbohuang×GK5, Ms101×GK5, MsleafyYunyan87×GK7 and MsYunyan85×GK9. The broad sense heritability (HB) of potassium content in leaves was high at all potassium application levels, the narrow sense heritability (HN) only accounted for a small part of HB, and the percentage of SCA variances was higher than that of GCA in general, which indicated that gene effect greatly affected the potassium content in tobacco leaves, and non-additive effect was greater than additive effect.