This study systematically elucidated the molecular mechanisms by which plant hormones regulate the polygalacturonase （PG） gene family during lettuce seed germination， through an integrated approach involving microscopic morphology， hormone profiling， enzyme activity assays， and transcriptome sequencing. Scanning electron microscopy revealed that the radicle penetrated the endosperm cap to form a tearing surface after 15 h of imbibition， with penetration completed by 24 h. Germination assay showed nearly 100% germination by 36 h. Treatment with 10 μmol/L gibberellin （GA?） and 1 mmol/L ethylene （ETH） shifted the peak germination probability forward to 18-18.5 h， accompanied by radicle thickening and increased root hair density. In contrast， treatments with 1 μmol/L abscisic acid （ABA）， 25 μmol/L jasmonic acid （JA）， and 10 μmol/L indole-3-acetic acid （IAA） delayed peak germination probability to 21.5 h， 27.5 h and 29 h， respectively， while also inhibiting radicle elongation. Analysis of endogenous hormones showed ABA， abscisic acid glucose ester （ABA-GE）， JA， and salicylic acid （SA） levels progressively declined during germination， whereas IAA and 1-aminocyclopropane-1-carboxylic acid （ACC） exhibited sustained increases. The superoxide anion （O₂^·-） production rate in imbibed seeds from the control group initially increased then declined. Treatments with GA₃， SA， and ETH enhanced the O₂^·- generation rate， while treatments with ABA， IA， and JA had minimal effect. LsPG enzyme activity exhibited distinct dynamics across treatments： activity peaked at 30 h for water/ETH， at 36 h for GA₃/ABA/IAA， and at 24 h for SA/JA. Notably， ETH， GA₃， and SA treatments most significantly enhanced LsPG enzyme activity. Through genome-wide analysis， 54 LsPG genes were identified for the first time in lettuce， clustering into seven subfamilies and being unevenly distribution across nine chromosomes. Subcellular localization experiments confirmed that LsPG4 and LsPG38 proteins localize to the cell membrane. Conserved motif analysis revealed that Motif 3 was ubiquitously present， while Motif 2/4 were widely distributed. All LsPG genes contained 2 to 10 exons. Cis-acting element analysis revealed that LsPG1/7/24 were enriched in hormone-responsive elements， with ABA-responsive elements being the most abundant. qRT-PCR analysis revealed hormone-specific expression patterns of LsPG genes： GA₃ significantly upregulated LsPG4/20/47/53 （4.5/3.2/3.3/3.1 fold）； ETH specifically activated LsPG47 （3 fold）； IAA induced a 7.3 fold increase in LsPG20 expression， JA induced LsPG2/13/22； SA suppressed LsPG19/20/24， with LsPG19 expression being inhibited by ABA/SA/GA₃/IAA/ETH/JA. Overall， this study demonstrates that GA₃/ETH promote endosperm cell wall degradation via LsPG activation to accelerate germination， whereas ABA and SA delay germination through LsPG inhibition. The hormone-PG gene interaction network model provides a theoretical basis for deciphering the mechanism of lettuce seed germination and molecular breeding.