National research funding regulates government research expenditures and thus greatly affects the sustainability of the academic disciplines. This study examined the sustainability of linguistics based on national research funding over the past 20 years (2000-2020). In particular, we used a bibliometric approach to examine the evolutionary trends in the number of topics, important factors, and major research themes in the field of linguistics based on the National Social Science Foundation (NSSFC). The main findings are three-fold and summarized as follows. First, a significant increase in awarded grants in linguistics was found over the examined periods. Second, influential factors such as regions, institutions, and academic ranks significantly affected the likelihood of receiving research grants. Third, eight major research themes were identified, along with their evolving trends. These identified research themes were similar to those in previous studies and focused on basic research. The results further indicate: (1) linguistics as an academic discipline in China has undergone sustainable growth over the examined periods; (2) close attention should be given to critical factors that affect the chance of receiving research grants; (3) research grants reflect government’s strategic plans to sustain the growth of academic disciplines; (4) research grants can work as a helpful tool for mining research information. Practically, while the present study has taken China as the representative case, the methods in use nevertheless have high ecological validity, thus being applicable to future studies concerning mining research themes from voluminous, diachronic text data. Besides, the current results can also serve as practical references for prospective researchers and applicants in their decision-making process.