We construct a complex network of the middle latitude circulation system of north hemisphere (NCNH). The decadal characteristic of leading teleconnection and its probable correlation with abrupt climate change are analyzed base on the circulation system network. Results show that (1) action centres of NAO, EUPA and WP have all moved during different periods in the recent 40 years and there has been a common abrupt change process as the end of the 1970s and beginning of the 1990s separately; (2) the new index which denotes the importance of teleconnection is defined using the node degree of NCNH. The temporal change of new index shows that the leading modes were PNA, EUPA and WP before the 1980s; index of NAO notably increased and all the five teleconnections were comparatively robust after 1980s; the index of AO notably increased and other modes comparatively decreased after 1987. So, center and index changes of decadal leading teleconnections may be another important phenomenon of abrupt climate change.