This paper discusses the features and formation mechanism of seismogenic structure, i. e. "extensional uplift and compressive depression". Analysis of the data of crustal deformation data of western Yunnan before the Ms = 7. 0 earthquake in Lijiang ascertains that there will be strong earthquakes in this region and evendetermines the exact site of the earthquakes. It is suggested that the impending and short-term earthquake precursory features of crustal deformation are various unstable changes, from "Stiff locking" of the seismogenic structure through "asynchronous acceleration", "separation inversion", and "uneven tilting" to "stagnation and calmness" or even to "vibration". According to the size and amplitude of the "Compressive depression-extensional uplift" and the elastic strain of rocks observed before the earthquake, the earthquake magnitude can be approximately calculated.