CO_2, CH_4 and N_2O are the most important greenhouse gases on global climate change. Since water-heat exchange between the soil and the atmosphere requires a certain time, there are different relationships between greenhouse gases and soil parameters,such as the temperature and humidity. Currently, researchers have concentrated in the studies of seasonal variations of greenhouse gas emissions, while diurnal variations were rarely reported. This study was conducted to investigate diurnal variations of CO_2, CH_4 and N_2O fluxes in the late growth stage of wheat (Triticum aestivuml) under conventional fertilization and no-fertilization treatments from wheat land in Beijing. In this study, artificial static chamber method was used for investigating CO_2, CH_4 and N_2O fluxes in situ continuously for 48 hours. The samples were collected every two hours and each time lasted 30 minutes. CO_2, CH_4 and N_2O were determined by gas chromatography (Agilent 6890A, FID, ECD), atmospheric temperature and soil temperature were also measured. The results showed that CO_2, CH_4 and N_2O fluxes had obvious diurnal variation tracks. Wheat land soil might be a sink of CH_4 but a source of N_2O and CO_2. The daily mean fluxes of CO_2, CH_4 and N_2O after fertilization were higher than those without fertilization. More than seventy percents of the fluxes of CO_2, CH_4 occurred in daytime. The N_2O emission fluxes under both fertilization and no-fertilization treatments during the daytime reached 81.8% and 91.1% respectively. There were highly significant (P < 0.01) or significant (P < 0.05) positive correlations between CO_2 fluxes and atmospheric temperature, soil temperature of 5 cm depth. Also there were highly significant (P <0.01 ) positive correlations between N_2O fluxes and soil temperature of 10 cm depth, thus the temperature might be a crucial factor in diurnal variations of CO_2 and N_2O fluxes. However, atmospheric temperature, soil temperature of 5 cm and 10 cm depth didn't impact CH_4 fluxes significantly.