Why does Huck try to save the murderers in The Adventures of Huckleberry Finn, and how does this reflect on his character?

I assume that you are talking about the theives and murderers who are aboard the riverboat during the storm.  This is the episode where Huck and Jim take the murderers' boat and leave them stranded on the riverboat, which is breaking up.

Huck tries to arrange for the murderers to be rescued because his conscience is making him feel bad about leaving them to die.  This, to me, shows that Huck has a very high character -- he does not want to cause the death of anyone, even if they are bad people.