A field experiment was conducted by using the static chamber-gas chromatography method to analyze the emission behavior of greenhouse gas (CO2, CH4 and N2O), and estimate the global warming potentials (GWP) of CH4 and N2O and the greenhouse gas intensity (GHGI) through different straw biochar application treatments in a maize field, including none biochar application (C0), biochar application rate of 15t/hm2 (C15), 30t/hm2 (C30) and 45t/hm2 (C45). Results showed that biochar application can significantly decrease the seasonal emissions of CO2 and N2O. The emissions of CO2 and N2O were decreased with the increase of biochar application rate, and the maximum decreases of CO2 and N2O emission were 24.6% (C15) and 110.35% (C45), respectively, compared with those of C0. The seasonal CH4 emission followed a decreasing order of C15, C30, C0 and C45, in which the maximum decrease of CH4 emission for C15 was 259.62% compared with that of C0. Biochar application can also decrease the comprehensive temperature increasing potentials (GWP) and the emission intensity (GHGI) of CH4 and N2O. The GWP of C15, C30 and C45 were reduced by 88.2%, 123.2% and 109.9%, respectively, and the GHGI were reduced by 88.86%, 121.60% and 100.03%, respectively, compared with those of C0. In addition, biochar application was able to increase maize yield. Compared with that of C0, the maize yield increases were 6.28%, 7.27% and 1.69% for C15, C30 and C45, respectively. The experiment demonstrated that C30 reached the most decrease of GWP and GHGI and increase of maize yield. Therefore, biochar application with a rate of 30t/hm2 can achieve the purposes of yield increase, carbon fixation and emission reduction under the current maize filed management measures.