The ability to predict the time-trend of earthquakes through seismic time symmetric characteristics is a significant step in earthquake disaster prevention and reduction. To verify the research approach of seismic time symmetry and reveal the mechanisms involved in seismic time symmetry characteristics, time symmetry characteristics and trends of M_S ≥ 7.0 earthquakes are analyzed and assessed by applying different methods such as commensurability calculations, the butterfly structure diagram, and the commensurability structure system. The seismic time symmetric characteristics are then explained in relation to types of cycles, such as the seismic energy releasing cycle, lunar right declination, and the sunspot cycle. Results show that:(1) the earthquake (M_S ≥ 7.0) sequence in the study area has evident time symmetry characteristics, and there are strong earthquake signals in 2017 with a random probability of occurrence of 65.5%; (2) the time symmetry characteristics of M_S ≥ 7.0 earthquakes provide a good intuitive expression of seismic energy releasing cycle; (3) the time symmetry characteristics of M_S ≥ 7.0 earthquakes results from the varying effects of superposition of lunar right declination and sunspot cycles, and the extremum of lunar right declination is the main trigger for strong earthquakes (M_S ≥ 7.0).