Assuming that the male and female are not desexed, it's likely that the female is pregnant and wants to get rid of the male now that she's nearly ready to give birth. The other option is simply that she's become territorial. If you got them as babies, as they mature (from 12 weeks onwards) they can get very hormonal and will try to establish dominance with each other. In any case, you need to separate them into two different hutches/enclosures, provide the female with a nest box (a shoebox with hay in it should suffice) and wait to see if she has babies. If she's not pregnant (31 days from mating to giving birth) then you will still need to keep them separated until you can get both of them desexed (if you want them to live together again). Rabbits that fight can cause very serious harm to one another, and even two rabbits of the same gender can most often not be bonded and live together unless both have been desexed.
If they are both already desexed, then you still need to separate them, or the fights and injuries could get worse. Sometimes rabbits simply don't continue to get along. Give them a break from each, and you can try re-bonding them in a month or so.
