The activists were formally accused yesterday of "picking quarrels and provoking trouble" in the central province of Henan, the US-based group Chinese Human Rights Defenders said in a statement citing relatives.
Acquittals in Chinese courts are extremely rare and the offence carries a maximum term of five years in prison.
Chinese authorities strictly limit public discussion of the June 4, 1989 crackdown when soldiers killed hundreds, by some estimates more than 1,000, protesters who had called for political reforms. They detained dozens of activists ahead of this year's anniversary.
Those arrested include former Tiananmen student leaders Chen Wei and her husband Yu Shiwen, and lawyers Ji Laisong and Chang Boyang, who represented a local disability rights organisation, the US-based Human Rights in China group said.
China's ruling Communist party does not tolerate organised dissent, and authorities have increasingly used the vague charge of "picking quarrels and provoking trouble" to target dissidents in recent months.
