I have dyed my hair from blonde to black and I hate it ,what can I do to get it lighter,light brown?

You better go to a harirdresser because trying to go lighter after you died your hair so dark is going to be hard and your going to damage your hair big time. Best advise is to visit a stylist.

In order to go from black to light brown or blonde, you must lighten the hair first with bleach and then apply a toner. If you use a box of permanent hair color to lighten your hair, it will result in a red/orange shade. Hair bleaching is a difficult process and should only be attempted by a trained hairstylist. Please see a professional if you want to correct your hair color.