[Objectives]  To identify late expression factor (LEF) genes and investigate the ClanGV infection mechanism. [Methods]  We analyzed the ClanGV LEF family of genes of Clostera anastomosis granulovirus, including gene identification and organization, gene sequences, and structural characteristics at the DNA and protein levels, and compared the data obtained with those on other baculoviruses. Open reading frames (ORFs) were confirmed using the ORF finder online program. Homology searches were carried out using the BLASTP program. Sequence data assembly and analysis were performed using DNAStar and DNAClub software. Sequence comparison in public databases was done using the BLASTprogram. Multiple sequence analysis was performed using ClustalW Version 1.8 and GeneDoc 2.7. Phylogenetic analysis was carried out with MEGA 4.0 software using the neighbor joining (NJ) distance method (1 000 bootstrap replicates). [Results]  Sequence analysis indicated that the C. anastomosis granulovirus ClanGV genome includes 15 LEF genes, annotated as ie-1, lef-2, 39k, lef-11, p35, p47, lef-1, lef-6, lef-5, lef-4, dnapol, lef-3, lef-9, lef-8 and lef-10, respectively. C. anastomosis granulovirus ClanGV shares higher homology with the Choristoneura occidentalis granulovirus, Agrotis segetum granulovirus, Cryptophlebia leucotreta granulovirus,  Phthorimaea operculella granulovirus, and the Cydia pomonella granulovirus, than with other granuloviruses. With the exception of 9 nucleopolyhedroviruses, P35 was only found in C. anastomosis granulovirus ClanGV and the C. anastomosis granulovirus. C. anastomosis granulovirus ClanGV lef-2 differed from that of the other 12 granuloviruses in transcription orientation. The nucleopolyhedrovirus belonging to gammabaculovirus and deltabaculovirus include 7 and 3 ClanGV lefs, respectively. C. anastomosis granulovirus ClanGV lefs have very low homology with baculoviruses, although their homology with granulovirus lefs is higher than with those of nucleopolyhedroviruses. C. anastomosis granulovirus ClanGV lef-2, 39k, p35, lef-5, dnapol, and lef-9, possess an early promoter motif (TATA). p47 and lef-1 have a CACT motif 20-40 bp downstream of TATA, and eight genes; lef-11, p35, lef-6, lef-5, lef-3, lef-9, lef-8, and lef-10, have a late promoter motif TAAG. However, only p35, lef-5, lef-9, and lef-10, possess both the TATA and TAAG. [Conclusion]  The results of this study are of considerable importance to research on the ClanGV granulovirus gene function and infection mechanism.