The relationship between strong arctic vortex and the La Niña events is found out by a case study of winter 2010-2011, using the NCEP/NCAR (daily and month mean) dataset. During the winter 2010-2011, the Arctic vortex was extremely stronger and persistent longer than normal, at the same time La Niña signals were surprisingly strong and long-lasting. The impact of La Niña on the polar vortex was investigated. Results show that the Pacific/North American (PNA) Pattern and corresponding temperature anomalies were forced by this La Niña event and the atmospheric circulation was greatly modified, too. Due to the negative heat flux in Aleutian region, the wave activities from the troposphere to the stratosphere were much weaker than their climatology. In addition, composite analyses also verified this La Niña’s impact on Arctic Vortex, where 13 strongest La Niña cases during the period of 1948?2010 were selected.