The carbon source/sink effect of land use change exhibits characteristics of interweaving natural and socio-economic processes,complex structure,and significant spatial differences. This effect can be examined from various perspectives such as landscape pattern,resource exploitation,dual attributes,and spatial effects. In order to comprehensively understand the carbon effect characteristics of land use change and its contribution to carbon reduction and sink enhancement goals,this study proposes a carbon source/sink effect framework of land use change based on composite ecosystem by summarizing multiple studies. Based on the logical relationship of this framework,we systematically organized the response characteristics,spatial effects,action mechanisms and assessment methods of carbon sources/sinks in typical landscapes,and investigated the ongoing challenges in research. The synthesis revealed that scholars generally concur: developed land acts as a carbon source,whereas forest,grassland,wetland,and arable land can function as both carbon sources and sinks. The assessment methods used include statistical models,remote sensing models,flux observation models,and ecosystem models,each with its own advantages and disadvantages and applicable conditions. Future research tends to be diversified and still needs to strengthen research on carbon sources/sinks in ecologically sensitive areas such as wetlands,balance carbon effects in different climate zones and land use types,improve various remote sensing monitoring and carbon emission monitoring databases,comprehensively consider the carbon effects caused by socio-economic and natural processes carried by land,and incorporate improving carbon sequestration efficiency into natural based solutions within the framework of composite ecosystem. This study enriches the research on carbon effects and carbon cycling of land use change from the perspective of precise evaluation of composite ecosystem,and can also provide decision-making references for carbon neutrality management.