Amira Osman Hamed faces a possible whipping if convicted at a trial which could come on September 19.
Under Sudanese law her hair and that of all women is supposed to be covered with a "hijab" but Hamed, 35, refuses.
Her case has drawn support from civil rights activists and is the latest to highlight Sudan's series of laws governing morality which took effect after the 1989 Islamist-backed coup by President Omar al-Bashir.
"They want us to be like Taliban women," Hamed said in an interview with AFP, referring to the fundamentalist rebel movement in Afghanistan.
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Activists say the vaguely-worded law leaves women subject to police harassment and disproportionately targets the poor in an effort to maintain "public order".
Hamed said she was visiting a government office in Jebel Aulia, just outside Khartoum, on August 27 when a policeman aggressively told her to cover her head.
"He said, 'You are not Sudanese. What is your religion?'"
"I'm Sudanese. I'm Muslim, and I'm not going to cover my head," replied Hamed.
Her dark hair, tinged golden, is braided tight against her scalp with a flare of curls at the back.
Hussein was fined for wearing slacks in public but she refused to pay. She spent one day behind bars until the Sudanese Journalists' Union paid the fine on her behalf.
Others rounded up with her in a restaurant were flogged.