Abstract The experimental biochemical methane potentials (BMP) of typical food waste (FW) and straw from northern China were individually measured in a 1 L enclosed reactor at 35 °C, and were 0.26 and 0.16 m 3 /kg-VS (volatile solids), respectively. Lab-scale mixtures of different FW and straw composition were conducted with a total organic load of 5 g VS/L. The optimum mixing ratio of FW to straw appears to be close to 5:1, and the methane production yield (MPY) reached 0.392 m 3 /kg-VS, i.e., increased by 39.5% and 149.7% compared with individual digestion results, respectively. Moreover, the gas production (GP) and methane content was reaching 0.58 m 3 /kg-VS and 67.62%, respectively. Further study about the optimal straw particle size was explored, and the recommended size range of straw was 0.3–1 mm for the economical and energy-saving consideration.