Organic compounds can be used as additives to regulate the morphology and structure of materials in the process of nanomaterial synthesis, thereby affecting the catalytic and electrochemical properties of the materials. In this paper, the nanomaterial Co₃O₄ was synthesized by hydrothermal method using disodium ethylenediamine tetraacetate (EDTA-2Na) as the additives and cobalt acetate as the cobalt source, and its structure and gas sensing properties were measured. The relationship between structure and gas sensitive properties was studied, and the mechanism of EDTA-2Na in the synthesis of materials was discussed. The results show that the complex formed by Co ²⁺ and EDTA ^2- regulates the growth direction of Co₃O₄ nuclei to generate the hexagonal nanosheets of Co₃O₄ with a side length of about 50 nm and a mesoporous structure. The response values of gas sensors fabricated by the Co₃O₄ nanomaterials to 100×10 ^-6 toluene and 100×10 ^-6 acetone are approximately 104 at 205 ℃ and 70 at 225 ℃, respectively. The high response of the gas sensor to volatile organic compounds (VOCs) is attributed to a large number of defects on the surface of Co₃O₄ synthesized by EDTA-2Na, which improve the adsorbed oxygen content. In addition, the mesoporous structure and large specific surface area are conducive to the adsorption, surface reaction and diffusion of VOCs. In this study, an effective method is proposed to obtain a highly responsive VOCs gas sensor by adding EDTA-2Na to synthesize Co₃O₄ nanomaterials.