Abstract: According to some identified cDNA sequence of the polyneuridine aldehyde esterase（PNAE） gene in plant species on the NCBI，pairs of primers were designed，and the partial intermediate sequence of the PNAE cDNA was obtained using RT-PCR technique in Rauvolfia yunnanensis’ fresh leaves，and then by the technique called rapid-amplification of cDNA ends（ RACE），the sequence in both two flanks of the known sequence was acquired. The full length sequence of the cDNA of PNAE in Rauvolfia yunnanensis was 1 004 bp and that included an open reading frame（ORF）which encoded 264 amino acids. Sequence analysis showed that for PNAE gene the homologies of amino acid sequence among each species was a little low ranging from 40% to 60%，demonstrating PNAE gene wasn’t a gene that its complete sequence is relatively conservative. The further analysis of all the known PNAE in plant species found that there are two conservative domains in amino acid sequence，revealing that PNAE gene has two highly conserved domains among different plant species.