Chitin is one of the most important and abundant compounds of the nematode egg wall, including sugar beet cyst nematodes. Sugar beet cyst nematode (Heterodera schachtii) is one of the most important pathogens in sugar beet in Iran. The ability to produce these enzymes has been evaluated by various antagonistic fungi. Chitinases are the most important. Extracellular enzymes such as beta 1, 3 glucanases, cellulase, and chitinase are produced by fungal biocontrol agents. Chitin is converted into n-acetylglycosamine subunits after digestion by chitinase enzymes. This study was carried out to determine the relative production potential of chitinase enzyme by 6 isolates of the fungus including Simplicillium lanosoniveum, Botryotrichum peruvianum, Alternaria chlamydospora, Penicillium chrysogenum, Acremunium sp and Fusarium solani. Experiments were carried out on fungi isolated from cystic nematodes. In this study, fungi were cultured on a culture medium containing colloidal chitin 5%, and the levels of their chitinase enzyme production were relatively evaluated. Relative analysis of chitinase activity showed that Acremunium sp, Penicillium chrysogenum, Fusarium solani isolates had the most and fastest variations in color to violet, indicating the highest production of chitinase enzyme by these fungi. Acremunium sp was more and faster than other isolates. The lowest chitinase production was obtained by isolates of Botryotrichum peruvianum, which showed the slightest and slowest color changes in comparison with other isolates. Although some of the isolates showed excellent results in all three tests, however, due to the fact that some of these isolates themselves are pathogenic for plants, further studies and necessary precautions are required for their use in biological control Recommended.