The invention provides a long non-coding RNA (long non-coding RNA, 1ncRNA)-incRNA-HN3 sequence relevant to human melanoma cells, and an RNA interference (RNA interference, RNAi) target spot sequence, a short-hairpin RNA (short-hairpin RNA, shRNA) sequence, an shRNA coded small molecule interference RNA (small interference RNA, siRNA), a coding shRNA coding strand and an anti-sense strand DNA sequence, coding shRNA recombinant plasmids of the long non-coding RNA sequence, and the invention relates to the applications of the long non-coding RNA sequence for preparing reagents for diagnosing melanoma diseases and drugs for treating the melanoma diseases.