Chow is charged with inciting others to join an unauthorised rally on June 4.
Chow was detained on June 4 on suspicion of publicising the rally and was later granted bail. She was then taken into custody by the police in late June and denied bail by West Kowloon Court.
After hearing arguments from the defence and prosecution on Thursday, justice Judianna Barnes decided to free Chow on bail of HK$100,000, but she needs to report to the police regularly and cannot leave Hong Kong.
The activist has pleaded not guilty. Her trial is set for October 5 and is expected to last two days.