A container data center includes a container, a group of server systems located in the container; a hot aisle and a cold aisle formed at two opposite sides of one group of server systems, a fan apparatus located at a top of the hot aisle, a heat exchanger located adjacent to the fan apparatus and opposite to the hot aisle; a cold airflow buffering area formed at a top of the cold aisle, and blades located below the cold airflow buffering area. Fan apparatus draws in hot airflow from hot aisle into the heat exchanger. The heat exchanger transforms the hot airflow into cold airflow and exhausts the cold airflow into the cold aisle through the cold airflow buffering area and the blades. Swinging angles of the blades are adjusted according to wind speeds of the cold airflow through the blades to obtain a uniform flow.