On 11 March 2011, a great earthquake with magnitude 9.0 has occurred in Tohoku, Japan, more than 1,000 km from South Korea. In fact, seismicity rate in South Korea has increased since the 2011 Tohoku earthquake, although detailed evaluation of its effects on the Korean Peninsula remains incomplete. Now, the high precision space geodesy techniques play a key role in monitoring the crustal strain state and energy variation. This study attempts to evaluate crustal deformation around the Korean Strait after 2011 Tohoku earthquake through a detailed analysis recorded by GPS. Moreover, this study found a different fault characteristic in Japan affect the station displacement prior to GPS data observed among 2011 to 2012. After a year, the strain in Japan found in direction WNW-ESE, while in Korea found in direction WSW-ENE. This finding suggests the likelihood of the existence of a certain tectonic line between the southern part of Korea peninsula and Japan.