Who has the right to property when a mother dies without a will her daughter or her daughter's stepfather?

Let's see . . . the natural daughter's stepfather would be the husband of the decedent. He would be the surviving spouse. Generally, the surviving spouse of someone who dies intestate (without a will) is the primary heir. Each state has its own laws of intestacy and they vary from state-to-state. You would need to check your state laws to determine your status as an heir-at-law. You can check your state law at the related question link below.