A trip to the vet is always the first thing suggested. The vet can determine if there's anything medically wrong that may be causing the vomiting. Is your cat acting nauseous? Licking the lips, meatloafing, etc?
If your cat gets a clean bill of health, then take a look at the food. Would a canned food diet be easier on your cat's tummy than dry food? Is she eating too fast? Would a dry food in smaller pieces be easier to eat?
I've found that cats tend to throw up dry food a lot more than they throw up wet. They don't chew it properly, just swallow the pieces whole. This then expand when it gets wet in their stomachs and causes them to suddenly feel too full and then throw up.
Have you tried your cat on wet food? Has dry food always caused her to throw up or is this a recent thing?
As @LTS3 said, a trip to the vet would be the best thing to do. Once you are sure she is healthy you can try changing her diet to see if that helps.