The triplet method is an analysis method based on the time frequency of the M > 7.0 earthquakes.A specific approach is used for studying the time series of great earthquakes occurring in the past in a certain region by using a time series composed of periodicity,multiple periodicity,and golden section.If they fit well,we can use it for predicting the time of a future earthquake by the time series."Activity in quiescence" is a method for analyzing the seismic activity on the basis of considering the earthquakes in a low-tide period as a precursory index for predicting the earthquakes in a high-tide period.It calls approximately one decade when no M >7.0earthquakes occurred in the Mainland China intermittent period,then subtracts two years from both ends of the intermittent period to eliminate the influence of the start and the end of the earthquake climax;hence,the rest of the period is called the quiet period.In the places where M6.0earthquakes occurred in the quiet period,the M ≥ 7.0earthquakes may occur when the climax of the next earthquakes is reached.By aiming at the Minxian-Zhangxian MS6.6earthquake that occurred on July 22,2013,in this paper,we reviewed and analyzed the apparent precursors and prediction process before the earthquake with the triplet method and"activity in quiescence"method.The results show that, after using the triplet method to analyze historical earthquakes of magnitude 8,magnitude 7 and magnitude 6that occurred in the southeastern Gansu,in 2012we predicted that an MS6earthquake would occur in Tianshui in the 2013-2014period,and the prediction location was withina 150km radius of Tianshui.In addition,because the magnitude and seismogenic year of the Diebu MS5.8earthquake occurring on January 8,1987were similar to the index of"earthquake of activity in quiescence",we used this earthquake as the index of a"quasi-activity in quiescence",made a time prediction with the triplet method,and then predicted that from 2012to 2014,an MS6~7earthquake would occur in a 150km radius of the location of the Diebu MS5.8earthquake.Because of the complexity of earthquake prediction,after analyzing the whole country and Gansu province by using the index of the triplet method and"activity in quiescence"method,we found that there were more significant precursor shows in other regions,so the prediction on the southeastern Gansu was just listed in the second program of earthquake risk.In 2012we only obtained an investigational prediction result,but not put forward a prediction advice.The reality is that the Minxian-Zhangxian MS6.6earthquake occurs in the location of a"quasi-activity in quiescence" earthquake;however,this earthquake shows that the triplet method and"activity in quiescence"method still display earthquake precursory indicators,and the"quasiactivity in quiescence"indicators are worthy of attention.Comparing to the commonly used prediction methods for medium-term prediction,the triplet method can point out a specific time period in the background of strong earthquake,which is its obvious feature.If combined with a variety of other methods,the triplet method will further enhance its efficiency of predicting strong earthquakes.