A suspicious object was found on Newtownards Road at about 22:00 GMT on Wednesday.
Army bomb disposal experts examined the object and have declared it to be a hoax.
The Newtownards Road was closed between Holywood Road and Grampian Avenue, but reopened to traffic just after 01:00 GMT on Thursday.
Naomi Long, Alliance Party MP for east Belfast, said: "This incident is yet another senseless attack on the whole community, with the business and residential life of the local area again subjected to unnecessary disruption."
A security alert at the Alliance party offices in east Belfast has ended.