As a plant-specific transcription factor family， the TIFY family plays an important regulatory role in various plant physiological processes such as seed development， signal transduction and stress response. In this study， based on the soybean genome data， including combined with the transcriptome data related to seed development and seed size， we performed genome-wide identification and systematic analysis of the soybean GmTIFY gene family using bioinformatics approaches. Furthermore，candidate genes responsive to soybean seed size were mined through protein-protein interaction network analysis， qRT-PCR and comparative genomics. The results showed that a total of 26 differentially expressed GmTIFY genes were identified from the transcriptome data of soybean seed development. Combined with seed size-related transcriptome data， 16 candidate genes associated with seed size were further identified. Collinearity analysis revealed 12， 4 and 11 pairs of collinearity genes between Glycine max and Arabidopsis thaliana， Oryza sativa and Solanum lycopersicum， respectively. It was found that segmental duplication was the main driving force for the expansion of the GmTIFY gene family， and the evolutionary process of this family was subject to purifying selection. KEGG enrichment analysis indicated that GmTIFY genes were exclusively enriched in plant hormone signal transduction pathways. Through homologous comparison， 11 core candidate genes related to seed size were further identified in soybean， and their interacting proteins were all involved in the regulation of seed size. qRT-PCR validation showed that at 20 days of seed development， the expression levels of eight genes were significantly higher in small-seeded soybean varieties than in large-seeded varieties， while the expression of one gene was significantly lower in small-seeded varieties， further confirming that these nine genes may participate in the regulation of seed size. The results of this study provide a theoretical references and genetic resources for dissecting the molecular mechanism of soybean seed size regulation and discovering candidate genes for high-yield breeding of soybean.