Chow, who’s also a lawyer, was initially detained on June 4 for publicising the vigil commemorating the Tiananmen Square massacre in 1989.
She was later granted bail and was due to report to the police next week.
Police said on Wednesday she’ll be charged with inciting others to join an unauthorised assembly on June 4.
In a press briefing, Superintendent Chen Chi-cheong also said Chow was arrested for allegedly publicising and calling on people to join a banned rally on Thursday’s handover anniversary.
But he refused to say if the activist had called on people to take part in the rally before or after an appeals board upheld the police ban, saying investigations were still ongoing.
Chow will appear before Sha Tin Magistracy on Friday.
In a statement, the Hong Kong Alliance, which organises the annual vigil, condemned Chow’s arrest and demanded her immediate release.
The alliance insists people have the right to commemorate the Tiananmen massacre, and anyone prosecuted as a result should be released immediately and have their charges dropped.
Last updated: 2021-06-30 HKT 22:41