Objective To observe the effects of GABA _A receptor in the paraventricular nucleus (PVN) on anxiety-like behavior in mice. Methods Three normal KM mice were randomly selected to observe the expression of GABA _A receptors in the PVN using fluorescence immunohistochemistry. Additionally, twenty-four normal KM mice were randomly selected and divided into three groups based on the microinjection of different drugs into the PVN: Normal saline (NS) group (0.3 μL), GABA _A receptor agonist Isoguvacine (Isog) group (0.3 μL), and GABA _A receptor antagonist Bicuculline (BIC) group (0.3 μL), with 8 mice in each group. The anxiety-like behavior changes of the mice after microinjection of different drugs in the PVN were observed. Results GABA _A receptors were expressed in the PVN of mice. Results from open field, elevated plus maze, and marble burying tests showed that microinjection of GABA _A receptor agonist into the PVN did not induce anxiety-like behavior in mice (P>0.05), while microinjection of a GABA _A receptor antagonist promoted anxiety-like behavior (P<0.05). Conclusion The activity of GABA _A receptors within the PVN may be associated with anxiolytic effects in mice.