Batman is one of the DC Comics hero. He appeared in two Scooby-Doo Episodes.

Batman in 2000's

The Dynamic Scooby-Doo Affair

Here he and Robin helped the gang solve a mystery with counterfieters and fight Joker and Penguin

The Caped Crusader Caper

Here he helped the gang finding a missing proffesor who was kidnapped by Joker and Penguin.

More Info about Batman here

Batman's look in Scooby-Doo