In this study, the consortium of filamentous fungi affecting the metal protection of 04 types of grease (GOI/VN grease, salt-tolerant grease AMC-3/VN, PVK/VN grease, Russian PVK grease) was identified. Six steel-covering grease types exhibiting protection against fungal infections were taken for fungal isolation. Seven strains of filamentous fungi were isolated, characterized by colony morphology, analysis of ITS1-5,8S-ITS2 sequences, and abilities to produce extracellular enzymes (protease, amylase, cellulase, lipase). Besides, the influence of filamentous fungi on metal protection was evaluated by measurement of rust portfolio on metal surface after degreasing by using images ImageJ v.1.51 software. Among isolated strains, 07 isolates of filamentous fungi showing varieties in morphological colonies were selected and taxonomically identified as Penicillium chermesinum, Penicillium cuddlyae with over 98% similarity of ITS1-5,8S-ITS2 sequences compared with related ones deposited on GenBank (NCBI). Of those, 02 strains (M1.1 and M4.1) were capable of producing 4 types of extracellular enzymes. When utilizing Image J software to examine the effects of fungal isolates on the protective capabilities of grease covering materials against metal corrosion, rust spots with variable densities between 1.30%-18.66% appearing on the surface of CT5 steel were found to be formed by fungal attacks. The findings in present study therefore provide a fundamental basis for the effects of fungal growth on grease decomposition at the Hoa Lac Thach That/ Ha Noi testing area and further studies on damages caused by fungi to steel-covering greases as well as corrosion of the metal surface.