The AdaBoost algorithm is one of the most effective methods in area of Face Detection. Since this algorithm has been proposed, many indepth research and analysis and improvement was provided by researchers. This paper reviewed AdaBoost algorithm and its improvement. Beginning with AdaBoost algorithm, we focus on analyzing the adavantages and disadvantages of AdaBoost algorithm. After this, we made systematic analysis and presentation on these improvements, including simple classification. Finally, we conclude with several promising directions for future research.