In 2018，the relationship between Iran and Saudi Arabia has changed in stages. In the first half of 2018，bilateral relations continued to deteriorate，speech threats escalated and regional games intensified. From July to August，there were signs of easing relations between the two countries. Iran offered to improve relations with Saudi Arabia. Saudi Arabia also opened a representative office of Iranian interests in Jeddah. However，the terrorist attacks in Iran in September worsened relations between the two countries. Iran accused Saudi Arabia of being behind the terrorist attacks and vowed to retaliate by force. In October，the outbreak of the Kashuji incident brought about another subtle change in relations between the two countries. There will be no war between the two countries in the near future，but the economic sanctions and military threats imposed by the United States on Iran have added instability to the changes in relations between the two countries. In the medium and long term，there is a possibility of mitigation and improvement between the two countries.