[Objective] This study aimed to study the genes affecting division mode in the early embryonic development of Arabidopsis thaliana.[Method] Two T-DNA insertion mutants were isolated from the mutant library of A.thaliana inserted by T-DNA,and the embryonic development was reflected by phenotypes.[Result] Genomic PCR-WALKING analyses demonstrated that T-DNA insertion sites were in 5' non-coding region and promoter region of gene At4g20360 which encodes Rab GTPase RABE1b,and the two mutants were named as Atrabe1b-1 and Atrabe1b-2,respectively.Microscopic analysis on mutants revealed that there was an abnormal cell division pattern in early globular stage of embryonic development.In addition,RT-PCR analysis showed that gene At4g20360 was constitutively expressed in A.thaliana.[Conclusion] Gene At4g20360 affected the division pattern of early embryonic development in A.thaliana,and encoded protein GTPase RABE1b which may play an important role in cell division during the embryonic development of A.thaliana.