Based on the actual boundary conditions of indoor air environment, the characteristics of indoor source (VOCs) emission and sink effect were analyzed on the basis of the mechanism of building material emission and indoor surface sink behaviors in combination with CFD method. The selected factors reflecting indoor actual boundary conditions included the outdoor air quality of inlet, outdoor airflow, indoor air temperature and the area ratio of sink to source. The results have shown that the decline of inlet outdoor air quality and the increasing of outdoor airflow have opposite influence on indoor VOCs emission intensity and sink intensity, but the former may cause the mean concentration of indoor VOCs to rise and the latter may make it descend. Meanwhile, the impact of indoor air temperature on indoor VOCs emission intensity and that on indoor VOCs mean concentration have similar characteristics. This is also true of the effect of sink to source area ratio on indoor VOCs sink intensity and that on indoor VOCs mean concentration. In addition, it is an effective way to obtain the characteristics of indoor source emission and sink effect with the established source emission model, the sink model and the indoor actual boundary conditions.