Under the background of the “Belt and Road”, the water resource vulnerability(WRV)of Guangxi Beibu Gulf Economic Zone(GBGEZ)was calculated by function method from 2015 to 2030 and the impact of the “Belt and Road” on the WRV of GBGEZ was analyzed. The results show that the WRV of GNBEZ is at a “strongly vulnerable 1” level from 2015 to 2030. But the vulnerability index increases from 0. 236 to 0. 271, an increase of 14. 83%, which means the impact of the “Belt and Road” on the WRV of GNBEZ is large and water resources have great pressure on carrying out future social and economic development. Water resources of Beihai City are most vulnerable and the vulnerability index increases from 0. 544 to 0. 801, an increase of 47. 24%. The evaluation level raises from “extremely vulnerable 1” to “extremely vulnerable 2”, which means the implementation of the “Belt and Road” has the greatest impact on the WRV of Beihai City.