Based on the analysis of transcriptome and proteome data of embryos in the hybridization of Chrysanthemum morifolium var.‘Yuhualuoying’× tetraploid C. nankingense,a gene named Cm2S was identified that could express differentially in different stages of embryo development. Cm2S was isolated from normal embryos of‘Yuhualuoying’by a high-fidelity PCR,and the Open Reading Frame(ORF)length of Cm2S was 852 bp,encoding a protein of 283 amino acids. The SMART online website was used to predict the functional structural domains of Cm2S protein,the results showed that Cm2S protein belongs to the AAI_LTSS family and it has two conservative AAI(alpha-amylase Inhibitors)structural domains. Homology comparison and phylogenetic tree analysis showed that Cm2S had the highest genetic relationship with AaSSP6 in Artemisia annua. The result of subcellular localization showed that Cm2S was located in cytoplasm and nucleus. Quantitative real-time PCR(qRT-PCR)showed that Cm2S was specifically expressed in embryos,and the expression level in normal embryos at 18 days after pollination was significantly higher than that in the other two samples. It was 315.11 times of that in normal embryos at 12 days after pollination while 1.98 times of that in abortion embryos at 18 days,respectively.