The chalcone synthase gene (CHS) was cloned from Lilium oriental hybrid ‘Siberia’ by PCR method.Sense and antisense CHS were constructed into plant expression vectors pCAMBIA1304,and then transformed into tobacco by agrobacterium mediated approach.18 plants of sense CHS transgenic Nicotiana benthamiana and 21 plants of antisense CHS transgenic Nicotiana tabacum were obtained and the total transform ratio was 26.0%.High Performance Liquid Chromatography (HPLC) suggested that CHS expression accumulation amplified by 14.0%~59.7% in N.benthamiana transformed with sense gene,and the accumulation declined by 44.5%~76.4% in N.tabacum transformed with antisence gene compared to the wild type.The petals of the transgenic N.benthamiana had no color changes,but the petal color in some of the transgenic N.tabacum plants was faded.The results indicated that the transformation of CHS gene was an effective method to flower color regulation.