Abstract: The proposal of the “dual carbon” goal is an inevitable requirement for the construction of ecological civilization in China. Open-pit building material mines are the important source of building materials industry as well as the carbon sources and the potential carbon sinks. Analyzing the laws of carbon emission has the great significance of the realization of “dual carbon” goal. By the research on the carbon emission factors, the carbon sink capacity and carbon emissions are researched, the net carbon emissions model of open-pit building material mines is built as well. The net carbon emissions of open-pit building material mine ecosystem are increasing first and then decreasing, the peak value of carbon emission generally appears in the middle and late period of the mines service period, the peak value and peak time are negatively correlated with the proportion of mine slope, the zero point appears in the ecological greening stage, and then the carbon emission enters the negative value stage. According to the net carbon emission of mining ecosystems, the carbon emission cycle of mines is divided into three stages: carbon peak, carbon emission reduction（including carbon neutrality） and carbon zeroing. Combined with a building material mine in Western Hubei, the applicability of the model is verified. It has a certain reference role for the study of carbon emissions in the building materials industry. At the same time, it also could be a guiding role for ecological restoration and green mine construction of building materials mines.