The purpose of this study was to explore the regulatory role of arginine decarboxylase (ADC) in core browning of Yali pear. Using Yali pear as material， the arginine decarboxylase of Pyrus bretschneideri (PbADC) was identified， and the bioinformation of PbADC and the gene expression pattern of PbADC were analyzed. The results showed that the PbADC gene was successfully identified and contained a complete open reading frame of 2 193 bp that encoding 730 amino acids. The phylogenetic analysis showed that PbADC was very closely to ADC of Pyrus betulifolia， Malus domestica， Pyrus ussuriensis × Pyrus communis and Malus hupehensis， and the multi alignment analysis showed that PbADC containing the complete Orn_Arg_deC_N domain， the binding site of pyridoxal 2-phosphate of ADC family and two important enzyme activity sites. Bioinformatics analysis showed that PbADC was a hydrophilic unstable protein with theoretical isoelectric point of 5.23 and molecular weight of 78.403 ku， which was hydrophilic and non-transmembrane without signal peptide， and α-helix and random coil were the main secondary structure of PbADC. The core browning index of rapid cooling treatment group was higher than that of slow cooling treatment group. Quantitative PCR and enzyme activity results showed that the expression of PbADC increased at the early storange period and then decreased during the browning of Yali pear， and the change of ADC enzyme activity was consistent with the gene expression level. This study clarified the bioinformatics characteristics of PbADC protein and the differential expression of PbADC gene during storage， which provided a theoretical basis for further research on the mechanism of postharvest browning of Yali pear.