Abstract： The codon usage bias of the Marburg virus(MARV)genome and related influencing factors were investigated to provide a reference for preparation of vaccines and specific antibodies.In total,93 MARV coding sequences were retrieved from the GenBank database and analyzed with EMBOSS,Codon W,and SPSS 26.0,while plots were generated with SigmaPlot14.0 and GraphPad Prism 9.5.The effective number of codons(ENC values)of the MARV genomes for each protein ranged from 49.84 to 60.92,and the codon adaptation index was close to 0.7.Relative synonymous codon usage showed that GCA,AGA,AAU,GA A,GGA,AUU,CCU,and AC A were common high-frequency codons of seven proteins,and the codons with fa-voritism mostly ended with A/U.Neutral,ENC-Plot,and PR2 parity analyses indicated that the MARV codon usage prefer-ence was dominated by natural selection,followed by mutational pressure and various other factors.Comparisons of MARV gene codon usage frequency with four expression systems(Escherichia coli,yeast,human,and baculovirus)found differences in the codon usage frequency between MARV and E.coli.MARV codon usage favoritism was shaped by a combination of fac-tors,with natural selection playing a dominant role.The E.coli expression system was most suitable for in vitro expression of MARV proteins.