Tea is one of the oldest drinks in the world and due to weather condition, season, age and genetic diversity, the compounds of tea are different. In this study, fresh tea shoots, consisting of one apical bud and two adjoining leaves of clones 100, 278, 451 and DN, in three harvest seasons (spring, summer and autumn) were collected from Tea Research Institute of Iran (Lahijan). Seasonal variation of neutralizing the free radicals (DPPH), caffeine, chlorogenic acid, quercetin, catechin and epigallocatechin were assayed using HPLC. The results indicated that antioxidant activity increased from 1^st harvest (spring) to 3^rd harvest (autumn) in 100 and 451 clones, while the activity decreased in 278 and DN clones. Total protein in 100 and DN clones was not significantly different during three harvesting season. These results suggest that the ecological variations in different season are determining factor for the biochemical compounds of tea clones.