Psychological variables remain a much under-investigated sub-category of individual differences (IDs) compared with cognitive ones. The present paper aims to gain a better understanding of the psychological effects of bilingualism by investigating national identity (NI), a socio-psychological construct, based on big data, that has rarely been examined. Drawing upon the 2015 Chinese Social Survey (CSS), which utilised a nationally representative sample (N = 10242), we employed a 'more refined' version of hierarchical regression analysis on the influence of foreign-language (FL)-based bilingualism and other sociobiographical variables on NI. Out of the 18 initial independent variables, satisfaction with life (1.7%-2.2%) and age (1.2%-1.4%) emerged as important predictors for NI as their minimum effect size value ([delta]R[superscript 2], see the range in brackets) exceeded the 'typical' benchmark (1%); in contrast, the influence respectively from FL mastery (0.006%-0.040%) and FL use (0.000%-0.004%) was negligible. In other words, our key finding is that a person's FL-based bilingualism had little to do with his/her NI. Implications for China's plan to reform FL (e.g. English) learning are discussed, and future research directions are also proposed.