Abstract: In this study，the sucrose synthase（SUS）and sucrose phosphate synthase（SPS）gene families were identified from pear（Pyrus bretschneideri‘Dangshan Suli’） genome database，and their gene structure，phylogenetic relationship，protein conserved domains，chromosomal locations and gene evolution pattern were analyzed by bioinformatic approaches. Transcriptome data and quantitative real-time PCR were used separately to analyze the expression patterns of SUS and SPS gene families during the fruit development of low-sucrose‘Dangshan Suli’and high-sucrose‘Cuiguan’（P. pyrifolia）. The results showed 17 SUS genes（PbrSUS1–PbrSUS17）and 8 SPS genes（PbrSPS1–PbrSPS8）were identified in P. bretschneideri，including 3 subfamilies for SUS gene family（SUS1，SUSA and SUS2）. The expansion of PbrSUS and PbrSPS gene families distributed unevenly on 10 chromosomes were mainly caused by segmental duplication，and their evolutionary processes were affected by purify selection. PbrSPS3，PbrSPS4，PbrSPS8，PbrSUS2，and PbrSUS15 are the important genes in regulating the synthesis and accumulation of sucrose for pear fruit.

Key words: Pyrus, sucrose synthase, sucrose phosphate synthase, gene；bioinformatics analysis, expression analysis