There are particular shampoos made specifically for dogs. However, you can also use human shampoo on dogs. The best shampoo should be least fragrant and have the most base. It is even better if you use baby shampoo when cleaning your dog.
1 Additional Answer
Using human shampoo on a dog will not harm him but it is not recommended. Human shampoo does not have the correct pH level dogs needs to keep their coats silky and shiny. It may strip the oils in his coat.