After the May 12, 2008 Wenehuan Ms8.0 earthquake, the north-south seismic belt has probably entered a new active period of strong earthquakes. The spatial distribution of ML5. 0 seismic activity since the Wenchuan Ms8.0 earthquake shows that the seismic activity has significant difference between the northern and the central-southern section of the north-south seismic zone recently. The characteristics of the strong earthquake activity in the seismogenic area before earthquake on the north-south seismic zone and the current condition of ML5.0 seismieity, draw our attention to the risk for strong earthquake both in the central-southern section and the northern section of north-south seismic zone. After the M4.0 seismic gap of the southeast Gansu was broken by the event which occurred in the junction of Diebu and Minxian on February 23, 2011, and Qingehuan Ms5.4 earthquake occurring around the seismic gap on November 1, 2011, it reveals the enhancement of seismic activity at the gap and its surrounding. The analog of the evolution of the seismic gap before the 1990 Gonghe M7.0 earthquake shows a possibility of a magnitude 7.0 in the southeast of Gansu. Combining with the M7.0 recurrence period of major large-scale fault, a comprehensive analysis shows that we should watch for the Maomaoshan fault and the Jinqianghe fault of the northern section of the north-south seismic zone, the eastern section of Xiangshan-Tianjingshan, the Lingwu segment of Yellow River fault, the north margin fault of West Qinling, Liupanshan-Baoji fault, the Maq~n-Maqu segment of eastern section of East Kunlun. There exist the possibility for the occurrence of a event with magnitude 7.0 along these faults.