The present invention relates to a preparation process of a tea extract containing non-polymer catechins extracted from tea leaves at a high extraction percentage, having a caffeine/non-polymer catechins ratio almost equal to the natural composition of the tea leaves and having good flavor and taste with less coarse taste, which includes charging the tea leaves in a column type extractor and continuously feeding the extractor with cold or hot water. The invention also relates to a packaged tea beverage containing the tea extract.