Dean Hancock, 37, was released on bail tonight and will appear at Fareham Magistrates Court in Hampshire on February 12.
It comes a day after his father, the MP for Portsmouth South, was suspended from the party following the leak of an unpublished report into his conduct, which found "compelling" evidence of "serious and unwelcome sexual behaviour" towards a vulnerable woman constituent.
The charges come after the Coalition partners were mired in rows and threats of legal action over whether Lord Rennard should take up his seat in the Lords. He is refusing to apologise after denying allegations he sexually harrassed women.
Earlier, the Liberal Democrats have been accused of dragging their feet over allegations that one of their MPs made repeated unwanted sexual advances towards a vulnerable woman constituent.
Mr Hancock's suspension followed the leak of an unpublished report into his conduct, which found "compelling" evidence of "serious and unwelcome sexual behaviour" towards the woman who suffered a mental health disorder and had been sexually abused as a child.
However the woman's solicitor, Harriet Wistrich, said that it had taken the Lib Dem leadership three years finally to take action after the complaints about his conduct first came to light.
The latest row is a further blow to Lib Dem leader Nick Clegg who has been struggling to contain the fall-out from the case of Lord Rennard, the party's former elections supremo, who is alleged to have sexually harassed a number of women activists - a claim he denies.
Although Mr Hancock - who denies the allegations against him - voluntarily resigned the parliamentary whip last year while he contests a High Court civil action claiming sexual impropriety, he continued to sit as a Lib Dem member of Portsmouth City Council.
Ms Wistrich said that repeated attempts to get the Lib Dems to take action over her client's allegations had come to nothing.
She disclosed that in February last year she had received a letter from the office of the Lib Dem chief executive informing her the party "would not commence any investigation or take any other action in respect of the matter that you have raised".
After a Hampshire police investigation concluded there was no case to answer, Portsmouth City Council launched an inquiry into whether Mr Hancock had breached the council's code of conduct, but that has now been put on hold pending the outcome of the civil court action.
"There seems to be a pattern here of Lib Dems not dealing with the matter," Ms Wistrich told Sky News.
"My client's wish is for him to be held properly to account for his misconduct. We are exploring all avenues. It has taken us three years to reach this stage because every time she has gone down one regulatory procedure or another there's been no investigation or no decision made.
"I think that the Lib Dems have very belatedly suspended him from party membership, the council have been appalling in not taking action earlier. He still is a councillor, they could proceed now with the allegations that he has breached their council code of conduct,."
Ms Wistrich said that her client was particularly concerned because Mr Hancock had remained "a very active member of the party and an active Lib Dem councillor".