Based on a long\|term location experiment on Caliche soil in Changwu Station of Chinese Academy of Sciences, Changwu, Shaanxi, China, we monitored diurnal changes and seasonal changes of CO2 flux from soils in a continuous winter wheat (Triticum aestivum L.) cropping system by LI-8100 automated soil CO2 flux system, and soil dissolved organic carbon (DOC), soil microbial biomass carbon (MBC) were also measured during returning green, heading, jointing, filling and mature stages during the wheat growing period Six fertilization practices arranged as a block with 3 replicates from the long\|term experiment were selected, which consists of fallow (F), control (CK), farm yard manure (M, 75 t?hm-2), nitrogen (N, 120 kg?hm-2), nitrogen and phosphorus (NP, 120 kg N?hm-2, 39 kg P?hm-2 ), and nitrogen and phosphorus plus farm yard manure (NPM, 120 kg N?hm-2, 39 kg P?hm-2, 75t ?hm-2 ). The soil CO2 flux showed significant diurnal changes and seasonal changes. For the diurnal changes, the soil CO2 flux rate followed a single peak curve with time, and the maximum of soil respiration appeared about at 12:00 or 14:30, and the minimums between 0:00 to 3:00 or about 6:00. Fertilization significantly increased soil CO2 flux rate, and the order of CO2 flux rate under different fertilizations followed as NPM > M > NP > N > CK > F. For the seasonal changes, the soil CO2 flux rate was highest during the jointing stage, followed by late filling stage, and minimum rate appeared during heading stage. Soil water deficit contributed to most of reduction of soil CO2 flux rate during heading and filling stage. Fertilization significantly affect MBC and DOC, there were significant seasonal changes in DOC and MBC. For DOC, the order was filling stage > heading stage > mature stage> turning green stage > jointing stage in all treatments. For MBC, the order followed as mature stage > heading stage > filling stage > jointing stage > returning green stage, and except manure treatments (M, NPM), MBC in jointing stage was more than in filling stage in all treatments. The relationships between DOC, MBC and soil CO2 flux rate under different growth stages was low under the condition of same fertilization, on contrast, the relationships between DOC, MBC and soil respiration rate were significant under different fertilizations. Soil respiration measurement using the root-exclusion technique indicated that fertilization enhance root respiration. Averaged cross the growing stages, the contribution of the root respiration to soil respiration in CK, N and NP treatment, were 36%, 45% and 54%, respectively.