Ibrahim Sharif, who headed the secular group Waed, was freed on June 19 after spending four years in jail over his involvement in 2011 Shiite-led anti-government protests.
But he was re-arrested three weeks later for "violating the law".
Public prosecutor Wael Buallay, in a statement carried by state news agency BNA, said an unnamed individual was accused of "promoting political change through forceful means and threats and inciting hatred against the political regime".
"By inciting hatred and calling for violence to advance political changes, the defendant has revealed that he is still committed to his hateful and criminal activities for which he was previously convicted" even after his release by a "royal pardon, in which the defendant pledged to comply fully with the law", it said.
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It accused Sharif of promoting "violent disorder" in a "direct attempt to undermine stability in the kingdom and overthrow the regime", adding that he would remain in custody.
Opposition sources say the activist was taken back to prison after he criticised the government during a ceremony for a victim of the unrest that has rocked the kingdom.
The opposition in Bahrain, which is home to the US Fifth Fleet, is pressing for a constitutional monarchy and an elected prime minister.
At least 89 people have been killed in clashes with security forces since 2011, while hundreds have been arrested and put on trial, rights groups say.