Using wild-type Arabidopsis thaliana(Col-0), TC1A-GUS, TC1A-GFP reporter lines, and two independent overexpression lines(OE-TC1A#1 and OE-TC1A#2) as experimental materials, we first characterized the expression pattern and subcellular localization of TC1A—a previously uncharacterized MATH domain gene in Arabidopsis. We then performed integrated phenotypic, physiological, transcriptomic, and hormonal analyses on wild-type and TC1A-overexpressing plants to elucidate the role of TC1A in mediating drought tolerance. Subcellular localization revealed that the TC1A protein localizes to the plasma membrane and nucleus. Transcriptomic analysis indicated that genes differentially expressed between TC1A-overexpressed plants and wild-type (Col-0) plants were predominantly enriched in stress response and hormone signaling pathways. The transcriptional level of TC1A was up-regulated under drought stress, and overexpression of the TC1A gene significantly improved the drought tolerance of Arabidopsis plants. Hormonal profiling revealed no significant difference in ABA content between overexpressed plants and wild-type plants. However, the level of intermediate product 12-oxo-phytodienoic acid(OPDA) in the jasmonic acid synthesis process was significantly increased in TC1A overexpression plants, suggesting that TC1A regulates drought tolerance via OPDA signaling rather than ABA signaling.