IGS GIM data is used to analyze ionosphere information of Mw7.0 Lushan earthquake on April 20, 2013. The grid points near the epicenter are selected to analyze by the envelope method and draw abnormal global iono-spheric anomalies map. The analysis results show that there are obvious ionospheric anomalies on 14th April which is six days before the earthquake. The abnormal conjugate area is distributed along the equator and constantly mov-ing. By analyzing geomagnetic indices, solar activity level, etc, it shows that ionospheric anomalies and earth-quakes have a significant relationship.