Abstract: The activities of catalase, peroxidase and polyphenol oxidase of the tomato plants increased with the age of the plant. The activities of catalase, peroxidase and polyphenol oxidase of the zinc deficient plants were considerably low. In the later stage of the growth, the activities of catalase and polyphenol oxidase of the normal plants were 4 times higher than the zinc deficient plants. When the symptoms of the zinc deficient plants were observed in the early stage, the activity of peroxidase was higher than the normal plants, but it was lower when the plants showed serious symptoms. After zinc sulphate was added to the culture solution in which the zinc deficient plants were grown, the activities of these three enzymes increased gradually to the level of the normal plants. The time of their recovery was different, peroxidase came first, polyphenol oxidase the second and catalase the last.