Objective To discuss the effects of long non-coding RNA (LncRNA) Down syndrome cell adhesion molecule-antisense 1 (DSCAM-AS1) on the proliferation, invasion, and apoptosis of head and neck squamous cell carcinoma (HNSCC) cells through microRNA-431-5p (miR-431-5p)/ephrin A1 (EFNA1). Methods The expression levels of LncRNA DSCAM-AS1, miR-431-5p, and EFNA1 mRNA in cancer tissues and adjacent tissues of 47 HNSCC patients from January 2024 to December 2024 in the Affiliated Hospital of Jiangnan University were detected by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). SCC1 and FaDu cells were assigned into Ctrl group, sh-NC group, sh-DSCAM-AS1 group, sh-DSCAM-AS1+anti-NC group, and sh-DSCAM-AS1+anti-miR-431-5p group. The mRNA expression in each group of cells was detected by qRT-PCR; cell proliferation was detected by MTT assay; cell migration and invasion were detected by Transwell assay; cell apoptosis was analyzed by flow cytometry; protein expression in cells was detected by Western blot; dual-luciferase reporter gene assay was used to verify the targeted binding of LncRNA DSCAM-AS1 to miR-431-5p and miR-431-5p to EFNA1. Results The expressions of LncRNA DSCAM-AS1 and EFNA1 mRNA in HNSCC tissues were significantly increased, while the expression of miR-431-5p was significantly decreased (P<0.001). The A570 value, migration number, invasion number, LncRNA DSCAM-AS1, EFNA1 mRNA and protein, and PCNA expression in SCC1 and FaDu cells of the sh-DSCAM-AS1 group were lower than those of the sh-NC group and Ctrl group, while the apoptosis rate and miR-431-5p expression were higher than those of the sh-NC group and Ctrl group (P<0.001); the A570 value, migration number, invasion number, EFNA1 mRNA and protein, and PCNA expression in SCC1 and FaDu cells of the sh-DSCAM-AS1+anti-miR-431-5p group were higher than those of the sh-DSCAM-AS1 group and sh-DSCAM-AS1+anti-NC group, while the apoptosis rate and miR-431-5p expression were lower than those of the sh-DSCAM-AS1 group and sh-DSCAM-AS1+anti-NC group (P<0.001). Conclusions LncRNA DSCAM-AS1 may promote the proliferation and invasion of HNSCC cells, and inhibit cell apoptosis by targeting miR-431-5p/EFNA1.