Despite the fact that many novel initiatives have been put forward to reduce the carbon emissions of buildings, there is still a lack of comprehensive investigation in analyzing a buildings’ life cycle greenhouse gas (GHG) emissions, especially in high-density cities. In addition, no studies have made attempt to evaluate GHG emissions by considering the whole life cycle of buildings in Hong Kong. Knowledge of localized emission at different stages is critical, as the emission varies greatly in different regions. Without a reliable emission level of buildings, it is difficult to determine which aspects can reduce the life cycle GHG emissions. Therefore, this study aims to evaluate the life cycle GHG emissions of buildings by considering “cradle-to-grave” system boundary, with a case-specific high-rise residential housing block as a representative public housing development in Hong Kong. The results demonstrated that the life cycle GHG emission of the case residential building was 4980 kg CO2e/m2. The analysis showed that the majority (over 86%) of the emission resulted from the use phase of the building including renovation. The results and analysis presented in this study can help the relevant parties in designing low carbon and sustainable residential development in the future.