Abstract: In this study，the objective is to provide a reference gene for gene expression studies of Lilium. Based on the actin gene EST sequence of the cDNA library of Lilium regale Wilson，a full-length cDNA sequence was cloned from Lilium regale Wilson through rapid amplification of cDNA ends（RACE）method and the gene expression characters were analyzed by the real time PCR. The full-length cDNA sequence（GenBank：JX826390）designated as lilyActin from Lilium regale Wilson was 1 367 bp in length，contains a 1 134 bp open reading frame（ORF）encoding a 377 amino acid proteins，with 91 bp in the 5′UTR and 233 bp in the 3′ UTR. Homologous alignment shows that it shares over 80% nucleotide sequence similarity and over 98% amino acid sequence similarity with actins in other plants. The phylogenetic tree reconstructed on the base of amino acid sequences suggests that the relationship of actin between Lilium regale and Tulipa gesneriana is the most intimate. Real time PCR analysis revealed that lilyActin was constantly expressed in various organs of Lilium regale Wilson such as flowers，leaves，bulbs. The results showed that relative to other reference gene lilyActin can be more appropriate for Lilium.

Key words: lily, Actin gene, gene clone, expression analysis, reference gene