A field measurement was carried out in a court yard cave dwelling, a typical traditional dwelling in the Northern China. To investigate the effect of the courtyard on moderating the hush climate and improving the thermal environment of the courtyard style cave room, interaction amongst the ambient, the courtyard and its surrounding cave rooms by monitoring hourly changes of temperature, humidity and wind speed over the building. The results shown in this paper prove the ability of this dwelling to transform an extreme winter environment outside cave rooms into a better outdoor community space and will be helpful for modern architects to seek a low cost housing solution with concern for sustainable development in this region.