Calcium homeostasis modulator 2 (Calhm2) is involved in the modulation of Ca²⁺ activity and ATP release. Our previous work has demonstrated that Calhm2 plays a crucial role in the progression of depression by regulating the astrocytic ATP release. In order to further explore the role and mechanism of Calhm2 in the development of depression, we firstly predicted the ATP binding site (glutamine, amino acid 87) of Calhm2, and established a mouse line that carried calhm2 mutation by mutating the glutamine to alanine (Q87A). Secondly, by using the primary culture of astrocyte and ATP detection analysis, we found that Calhm2 Q87A mutation resulted in a significant decrease of ATP release in astrocytes. Furthermore, we found that the ATP release decreased in hippocampal slice from Calhm2 Q87A mutated mice. Importantly, Calhm2 Q87A mutated mice showed a higher susceptibility to develop depression-like symptoms than that of wild type mice when exposed to chronic unpredictable mild stress (CUMS). Taken together, we identified that Q87 site is important for Calhm2-mediated ATP release in astrocytes and this point mutation of Calhm2 promotes depression susceptibility induced by stress in mice. The present work further defines the molecular mechanism of Calhm2 in the development of depression, with the implication of a potential avenues for the diagnosis and therapeutics of depression-related diseases.