Abstract: Ionospheric delay is one of the  main error sources in satellite navigation system, whose correction accuracy directly affects the users’ positioning accuracy. With the BDS navigation satellite system (BDS) fully serving the Asia-Pacific region,there is an increasingly urgent need for BDS to provide users with highprecision positioning and navigation services. At same time, BDS integrates the basic navigation service and Wide Area Difference Service (WADS),  releases ionospheric grid information with high update frequency , which can effectively improve the positioning performance. This paper evaluates the service range and service performance of ionospheric grid information service of BDS using data from January 2017 to October 2018. The results indicate that the effective coverage area of ionospheric grid information basically covers China, with a correction deviation of 1.62 TECU and a correction rate of 86.7%. The correction accuracy of ionospheric grid information is lower and more fluctuating in winter with a correction rate of 82%, but higer 87% in other seasons. Both the correction deviation and correction rate are higer during the day than at night. In addition, ionospheric grid information shows strong ability to resist disturbance.