Geraniol synthase (GES), which is very important to the biosynthesis of geraniol, is one of the key enzymes in terpenoids pathways. Based on the transcriptome analysis of P.cablin, one unique sequence encoding GES was discovered and the primers for PCR were designed from it, the fulllength GES cDNA was cloned using RTPCR strategy and its bioinformatics analysis has been done. Gene expression profile of PcGES1 in leaves and stems of different development stages of four cultivars was evaluated using quantitative reversetranscription polymerase chain reaction (qRTPCR). The results showed that the gene GES in P.cablin, named as PcGES1, accession number KF926075 in GenBank, contains a 1 734bp open reading frame and encodes a predicted protein of 577 amino acids. Phylogenetic analysis indicated that the amino acids encoded by GES1 of P. cablin were closest to that of Ocimum basilicum. PcGES protein was located in chloroplast, no transmembrane district. qRTPCR analysis indicated that PcGES1 mainly expressed in leaves, and the highest expression was in old leaves. The expression pattern analysis of PcGES1 among four cultivars indicated that the expression pattern of P. cablin (Blanco) Benth. cv. shipaiensis was similar to P. cablin (Blanco) Benth. cv. gaoyaoensis, while that of P. cablin (Blanco) Benth. cv. hainangensis was similar to P. cablin (Blanco) Benth. This study provided a foundation for exploring the mechanism of terpenoid biosynthesis in P. cablin plants.