Bond of affinal kin,network of marriage are important topics in the fields of sociological and anthropological studies of rural China. Not a few scholars explore it from the angle of market circle and territorial element. Following the analytical routes of culture and beliefs,some researchers on Chinese rural religion also pay attentions to the closed relationship between bond of affinal kin and maintaining of religious beliefs. Based on the fieldwork in several Catholic communities in middle Hebei province,this paper approaches and rethinks the influences that elements of market,territory and beliefs play on the affinal kin of rural Catholics. It argues that the market and territorial factors can be used to address the marriage conditions of ordinary villagers in northern China. However,they are not applicable to the local Catholic communities whose mode of connection mainly depends on endogamy. The relative low percentage of believers in total population does not diminish its religious endogamous tendency. Bond of affinal kin of Catholic believers contains the dual attributes of secular and religious,showing a "double- edged sword" effect on the maintenance of local Catholics and development.