The agricultural use of composted sludge is an effective way to solve the problem of sludge recycling. Because sludge is rich in organic matter, agricultural use of sludge will affect the quality of soil carbon pool. In order to clarify the effects of sludge application on carbon components of two kinds of soils with different pH values, the effect of sludgeapplication on soil organic, inorganic carbon components and soil acidity were determined, and the relationship between soil inorganic carbon and organic carbon and soil pH value was explored. Under the wheatmaize rotation mode, two consecutive years 〖JP3〗experiment was carried out, four sludge addition amounts were 3.75t/hm2, 7.5t/hm2, 37.5t/hm2and 75t/hm2, respectively, and one blank control was provided, which were marked as H1, H2, H3, H4 and CK, respectively. The main conclusions were as follows: the organic carbon components content such as soil organic carbon (SOC), readily oxidizable carbon (ROC), dissolved organic carbon (DOC) and humus carbon (HSC) were increased with the increase of sludge addition. Compared with CK, the SOC, ROC, DOC and HSC of acidic sandy soil were increased by 82.39%, 25.62%, 158.33% and 30.77%, respectively, when the sludge addition was 75t/hm2 （P<0.05); the corresponding values were 84.36%, 49.26%, 340.00% and 354.90% in alkaline loam （P<0.05), and there was a very significant positive correlation among the organic carbon components in two kinds of soils （P<0.01). The application of sludge reduced the ROC distribution ratio (except when the amount of sludge was 3.75t/hm2), but increased the distribution ratio of DOC and HSC. However, the proportion of ROC and HSC was decreased, but the proportion of DOC was increased in acidic sandy soil. In addition, the content of soil inorganic carbon (SIC), active inorganic carbon (AIC) and pH value in alkaline loam were reduced due to application of sludge, and the pH value of soil was also reduced; however, AIC and pH value were increased in acidic sandy soil. There was a significant positive correlation between SIC and pH value of two kinds of soils （P<0.01). It can be concluded that application of composted sludge can produce different carbon effects on different acidbase soils. Therefore, sludge can be used in production practice to cultivate fertilizer or regulate the change of carbon pool quality in soil, and the acidification phenomenon of acid soil can be changed by adding composted sludge. 