To elucidate the molecular mechanism underlying the growth-defective phenotype of rh31, a loss-of-function mutant of the RNA helicase(RH) family member RH31, and to comprehensively understand the role of RH31 in plant growth and development, the wild-type Arabidopsis thaliana Col-0 was used as the control, and seed germination and seedling growth phenotypes of rh31 and PROAtCAPE3 homozygous knockout mutants atcape3 under normal culture conditions were statistically analyzed. The growth phenotypes of rh31 and Col-0 seedlings were observed by exogenous application of ethylene precursor ACC, ethylene signaling pathway inhibitor AgNO3, 6-benzylaminopurine(6-BA), indole-3-acetic acid(IAA) and gibberellin(GA). The expression levels of genes related to plant signal pathways were detected to determine the relationship between PROAtCAPE3, plant hormones and the growth-defective phenotype of the rh31. The results showed that compared with Col-0, the germination potential of atcape3 was reduced, which was consistent with the seed germination phenotype of rh31. It was indicated that the decreased germination potential of rh31 might be caused by the decreased mRNA levels of PROAtCAPE3. In addition, the rh31 mutant was found to exhibit decreased sensitivity to exogenously applied ACC and AgNO3, accompanied by elevated endogenous ethylene content, which was significantly consistent with the shorter primary root lengths of rh31. Moreover, the ABA synthesis and signal transduction pathway in rh31 were enhanced, which was consistent with its phenotype of reduced germination potential . In conclusion, RH31 may regulate plant growth and development in Arabidopsis thaliana by modulating the transcript level of PROAtCAPE3, the endogenous ethylene content, and the ABA signaling pathway.