The spatial and temporal distribution of atmospheric chloromethane (CH₃Cl) in China was investigated between 2012 and 2014, and the sources of CH₃Cl were evaluated by positive matrix factorization (PMF) according to PMF 5.0 (USEPA). Various concentrations of CH₃Cl were found throughout China, ranging from 506.4 ± 110.5 to 1132.1 ± 523.3 pptv, showing the characteristics of high in the southeast and low in the northwest. The correlation between CH₃Cl and chlorofluorocarbon-12 (CFC-12) at most sites was greater than 0.5 and presented regional characteristics. The distribution of CH₃Cl in China is related to the degree of economic development, the high-concentration sites were located in the economically developed eastern region. The CH₃Cl concentrations at western sites were similar to the global average and increased with latitude and altitude, indicating that this region was least affected by anthropogenic activities. The annual average concentrations of atmospheric CH₃Cl in the northeastern region were below 730 pptv but had strong seasonal fluctuations. Chemical production was the main CH₃Cl source in the northeast background areas (46%), while industrial combustion contributed 42% of the CH₃Cl in the northeast urban areas. Large seasonal variations combined with a high relative standard deviation were observed in the southern region. Relative to the southwest, in the southeast, the onset of lower concentrations was delayed until September–October, and higher concentrations persisted for longer. Chemical production and biomass burning were the main sources in the southwest, while Chemical production and solvent use were the main contributors in the southeast. The Beijing area is discussed separately as a super megacity. No obvious seasonal fluctuations were observed in the Beijing area. According to the source analysis, chemical production contributed approximately 60% of the atmospheric CH₃Cl in the Beijing area, while 15–24% was from solvent release.