Thyroid cancer is a commonly occurring malignant tumour within the endocrine system, the incidence of which has been increasing steadily in our country. It has been the focus and direction of research in recent decades to continuously explore the diagnostic markers and molecular mechanisms of thyroid cancer and provide new possibilities for the healing of patients. In this study, lncRNA DHRS4-AS1 was identified as the research target, and the regulatory function of abnormal expression of DHRS4-AS1 on thyroid cancer was discussed. Thyroid cancer (116) and non-cancer normal (82) tissue samples were collected in this paper, and the expression of DHRS4-AS1 and miR-222-3p in tissues and cells were evaluated by RT-qPCR. CCK-8 and flow cytometry were used to detect cell survival status. The mechanism of DHRS4-AS1 sponge miR-222-3p was analysed by dual-luciferase reporter gene detection. In the present study, DHRS4-AS1 was down-regulated in both thyroid tissue and cell samples, while miR-222-3p expression was elevated. The ROC curve reflected the diagnostic value of DHRS4-AS1 in thyroid cancer [area under the curve (AUC) = 0.887, sensitivity = 76.7%, specificity = 95.1%]. DHRS4-AS1 regulates the development of thyroid cancer by targeting miR-222-3p. In addition, in vitro experiments demonstrated that overexpression of DHRS4-AS1 (pcDNA3.1-DHRS4-AS1) inhibited the proliferation of thyroid cancer cells and promoted cell apoptosis, while down-regulating the level of miR-222-3p. DHRS4-AS1 acts as a miR-222-3p sponge in thyroid cancer, and overexpression of DHRS4 AS1 down-regulates cell proliferation and promotes cell apoptosis. These findings demonstrate the potential of DHRS4-AS1 as a diagnostic factor for thyroid cancer.