The Advertising Standards Authority (ASA) said such a distressing subject was likely to cause discomfort when presented in any medium.
The DVD case – which was sent out by mail last December - carried the text: "Kerry's father asked her to do the unthinkable. And then he filmed it."
A leaflet inside the DVD said: "The footage of Kerry is now with the police. As is her father, because she was able to talk to ChildLine."
The NSPCC said it recognised that some people would be sensitive to the "difficult" issues of child abuse.
Seven people complained that the text on the cover was disturbing and offensive, while one complainant said it could cause distress to individuals who had suffered abuse.
Another said the DVD was inappropriate for children to see. The NSPCC defended the DVD by saying its mailings helped donations and it was therefore important that they made an impact.
The wording on the outside of the DVD did not contain details of abuse, the children's charity added.
The ASA agreed: "We took the view that any discomfort inherent in the subject of child abuse ought to be balanced by the worthwhile purpose of raising awareness of it.
"We considered that recipients were likely to understand the importance of the issue the mailing presented and that individuals who had suffered abuse would be likely to appreciate the work of the NSPCC and the message contained within it.
"We considered that the ad made clear its intended purpose, but was not likely to cause excessive distress or serious or widespread offence."
The NSPCC said it welcomed the decision.
A spokesman said: "We regret that there were a few complaints about this but we recognise that some people will be sensitive to the difficult and complex issues of child abuse."