越来越多的观测数据表明,地震前大气电离会受到扰动。但目前学者研究主要集中于震前较短时间内电离特征分析,从事震前电离长期影响的研究较少。利用NASA官网发布的1999—2014年IONEX格式电离资料,对2008年5月12日发生在我国四川汶川M_s8.0、2013年4月20日四川雅安M_s7.0地震分析,发现地震区域上空大气VTEC突变存在中长期 More and more observational data indicate that the atmospheric ionization will be disturbed before the earthquake. However, the current researches mainly focus on the analysis of ionization characteristics in a short time before the earthquake, and few researches have been conducted on the long-term effects of pre-earthquake ionization. Based on the ionospheric data of IONEX format published from NASA website in 1999-2014, the M_s8.0 earthquake in Wenchuan, Sichuan Province, China on May 12, 2008 and the M_s7.0 earthquake in Ya’an, Sichuan Province on April 20, 2013 were analyzed. It is found that the atmospheric VTEC over the seismic area Mutations exist in the medium and long term