Soil samples were collected in every season of a year from the plow layer of a long-term fertilization experimental field at the Fengqiu Agro-ecological Experimental Station, Fengqiu County, Henan Province, China, for investigation of effects of fertilization regimes on population of soil Bacilli and its proportion to the total of bacteria, and for analysis of relationship between population of Bacilli and soil fertility. The long-term fertilization experiment consisted of seven treatments, i.e. organic manure (OM), half the rate of organic manure plus half the rate of N fertilizer (1/2OMN), fertilizer NPK, fertilizer NP, fertilizer NK, fertilizer PK, and the control (without fertilizer), of which each had four replicates. Results show that long-term fertilization, especially in treatments that involved organic manure and fertilizer P, increased the contents of soil organic C, total N, available N, P and K, and the increase in soil organic C varied in the range of 0.91~7.00 g kg^-1 in all the fertilization treatments, except treatment NK. Regime of the long-term fertilization also significantly affected populations of Bacilli and soil bacteria, which showed steady gradients in all the seasons, that is, the populations were significantly higher in all the fertilization treatments, except NK than in the control; in the treatments involving organic manure than in the treatments involving chemical fertilizers only; and in the treatment of balanced fertilization than in the treatments missing any one element. The population of Bacilli increased in all the treatments except treatment NK by a range of 0.02~0.54 lg (CFU g^-1) as compared that in the control. The ratio of Bacilli/bacteria was higher in summer and winter than in spring and autumn in all the chemical fertilizer treatments and relatively stable throughout the year in the treatments involving OM. Correlation analysis that the population of Bacilli was closely related to the contents of soil organic carbon and available P (p<0.01). All the findings demonstrate that, long-term application of organic manure is more conducive to build-up of soil fertility and growth and propagation of soil microbes, and that the population of Bacilli is a sensitive indicator of soil fertility.