The ionosphere is an important component of the solar-terrestrial space environment,and the ionospheric delay error is one main content of the transmission medium amended in GNSS and deep space exploration.GNSS multi-frequency users can use the combination of dual-frequency or multi-frequency observation to weaken the ionospheric delay error.For GNSS single-frequency users,it is mitigated by GNSS broadcast ionospheric model usually.The sunspots,flares and coronal mass ejection and other violent activities appeared on the sun,often cause anomalies in ionosphere,such as ionospheric disturbance and scintillation.It may degrade the accuracy of GNSS signals and affect the performance of GNSS Standard Point Positioning(SPP).In this article,the influence of solar activities on GNSS broadcast ionospheric model was analyzed in Asia-Pacific region.Twelve X-class and M-class large solar flares are investigated and analyzed.Total electron content(TEC)data derived from IGS and Crustal Movement Observation Network of China(CMONOC)are used to analyze the variation of TEC and the accuracy of GNSS broadcast ionospheric model during solar flares.It is verified that there is the Sudden Increase in Total Electron Content(SITEC)occurred during the intense solar flare.Furthermore,the temporal variation of ROT is more obvious and rapid compared with TEC.Especially,the influence of solar flare on accuracy of GNSS broadcast ionospheric model is very dramatic.The adaptability of GNSS ionospheric models to solar activity is different.BDS broadcast ionospheric model outperforms the GPS and Galileo model when the intense solar flare occurred.The accuracy of Galileo model is the highest under solar activities,but the BDS model shows worse.It also shows that SITEC and the accuracy variation of GNSS broadcast ionospheric model caused by solar flare are related to the class of solar flares and position of stations.