With the increasing pace of industrialization and economic growth, the continuous increase in household waste has become a great concern all over the world. Residents' participation in household waste sorting is an effective way to promote the recycling of household waste. How to effectively promote more residents to participate in waste sorting has become an important issue of the government. Previous research mainly used two methods in exploring residents' intention to sort waste: qualitative case studies to explore potential causal descriptions and statistic studies with the structural equation modeling. These researches, however, consider one special case or the net effect of a single factor, which fails to present the comparisons across international contexts and hardly clarifies the complex pathways to residents' participation. In this research, a novel method fsQCA (fuzzy-set qualitative comparative analysis) is applied to explore the pathways both from a macro-level perspective and in different national contexts. Results suggest four different pathways influence residents' participation in waste sorting. In the four pathways, GDP level and source separation system are key causal conditions to influence residents to sort waste, but different configurations of these conditions influence whether residents participate in waste sorting at a high rate. Only when the external conditions and the socio-demographic conditions are combined in a specific form, residents participate in waste sorting at a high rate. At last, the findings provide some exercisable suggestions for decision makers in developing countries to design promotion programs and waste sorting policies.