Straw decomposition plays an important role in soil carbon sequestration. Litter quality and climate condition are considered to be key factors that regulate straw decomposition. This study investigated the decomposition characteristics of wheat and maize straw under cold temperate, warm temperate, and midsubtropic climate conditions, and examined whether the chemical structures of straw residues became similar during decomposition under different climate conditions. Straws were put in 0.074-mm-mesh size litter bags to exclude soil fauna and buried in black soil plots at three experimental stations located in the aforementioned climate regions to rule out the impact of soil type. The decomposition rate constants of wheat straw and maize straw increased linearly with temperature, and the former was more sensitive to temperature. Climate conditions and straw quality had marked effects on the residual material structure in the first half year of decomposition, but then decreased. Wheat and maize straw showed...