PIFs (phytochrome interaction factors) are the key negative regulators of light signal response. As the core member of the family, PIF4 plays a critical role in response to the changes of light and temperature, integrating multiple hormone synthesis and signal transduction. Shadetolerant soybean ‘Nandou 25’ (ND25) and shadeintolerant soybean ‘Rongxian Dongdou’ (RD) were applied to clarify the function and shadeinduced expression response of GmPIF4s ［phytochrome interaction factor 4s of Glycine max (L.) Merr.］ in soybean. In this study, the bioinformatic characteristics of leguminous plant PIF4s were compared and analyzed by bioinformatics and molecular biology methods. We analyzed the expression characteristics of GmPIF4s by qRTPCR in different tissues of soybean (root, stem, leaf and shoot meristem) in different shading time points under full light and 12 h/12 h photoperiod, and in different shade tolerant soybean cultivars, in order to provide a theoretical basis for highyield and shadetolerant soybean breeding. The results showed that: (1) 53 homologous PIF4s were associated with legumes by bioinformatic analysis, among them, soybean contains 7 homologous GmPIF4s. The length of amino acid is between 296-562 aa, and the molecular weight range is 41 491.9-62 228.39 Da. All GmPIF4s were hydrophilic proteins with bHLH domain, no transmembrane structure and located in nucleus. The secondary and tertiary structure prediction of GmPIF4s showed that the structure of GmPIF4a and GmPIF4b were most similar to the AtPIF4. (2) qRTPCR analysis showed that the expression of GmPIF4s were tissuespecific, in the shadetolerant soybean ND25, the relative expression levels of GmPIF4a, GmPIF4b and GmPIF4d were the highest in root, leaf, stem and shoot meristems. Except for GmPIF4a, GmPIF4e and GmPIF4f, other GmPIF4s were upregulated in all tissues above ground. In the shadeintolerant soybean RD, GmPIF4a, GmPIF4b, GmPIF4c, and GmPIF4d have relatively high levels in leaves. Except for GmPIF4f and GmPIF4g, the expression of other GmPIF4s in the above ground tissues was relatively high. (3) With the increase in shading time, GmPIF4a, GmPIF4b, GmPIF4c and GmPIF4d genes were strongly induced by shade treatment, and their expression levels are significantly upregulated; under 12 h/12 h photoperiod condition, no matter under normal light or shade, the expression of GmPIF4s showed a downward trend during the day, but an upwardregulated expression trend at night. It speculated that GmPIF4s expression is regulated by the circadian rhythm. (4) The expression of GmPIF4s in different shadetolerant soybean cultivars under shading condition showed that the expression of GmPIF4a, GmPIF4b, GmPIF4c and GmPIF4d in shadetolerant and shadeintolerant soybean cultivars ND25 and RD were all upregulated with the extension of shading time. However, the expression level of GmPIF4s was higher in the shadeintolerant soybean cultivar RD than that in shadetolerant soybean cultivar ND25, and the difference of GmPIF4s expression between the two soybean cultivars reached a very significant level after 8 hours of shading treatment.