Det Con Chris Maitland, 40, faces 14 charges, including sexual touching of a girl aged under 13 and making indecent images of a child.
The officer appeared at Westminster Magistrates' Court earlier and was remanded in custody.
He is next due to appear at Southwark Crown Court on 15 April.
Det Con Maitland, who works in the force's Sexual Offences, Exploitation and Child Abuse Command, was originally arrested in November on suspicion of possession and distribution of indecent images of children.
He was arrested again on Tuesday on suspicion of sexual touching of a young girl in Waltham Cross, Hertfordshire, in October 2005.
It is alleged the officer, of no fixed address, possessed 818 images and videos, ranging from the most serious category A to the lowest category C.
He also faces five counts of taking an indecent image of a child and seven of making an indecent image of a child.
Mr Maitland is currently suspended from duty.
A Met Police detective working in a child abuse investigation unit has appeared in court accused of a string of child sex offences.