Pornthip Munkong was brought to Bangkok on a June 2 arrest warrant.
She was a former coordinator of Prakai Fai Karn Lakorn, a group that produced a political stage play called The Wolf Bride to commemorate the 40th anniversary of the Oct 14, 1973 uprising at Thammasat University on Oct 6 and 13, 2013.
She was the director and script writer of the play.
A lawyer from the Lawyers for Human Rights Centre sought bail for her by placing a surety of 500,000 baht but the court denied her bail, citing flight risk.
She was the second person prosecuted for their roles in the play.
Ms Pornthip, 23, graduated from Ramkhamhaeng University's Faculty ogf Political science. She is keen on politics and stage plays.
Together with friends, she formed the Prakai Fai Kan Lakorn group in 2010 to produce plays the grassroots could more relate to. The plays involve social and political issues.
The group dissolved two years later due to internal conflicts.
On Thursday, a Khon Kaen University student who played an adviser to a fictional king in the play was arrested.
The court denied him bail, also citing flight risk as the penalty was high.
Under Section 112 of the Penal Code, anyone who defames, insults or threatens the king, queen, the heir-apparent or the regent, shall be punished with imprisonment of three to 15 years.