My horse had that same problem and my trainer put a ground pole one stride before the jump and it makes your horse slow down and think
there is no secret, you need to calm down and trust your horse :p
Stay focus on the other side of the fence, your head up and your back really straight in order not to bend with your shoulders , keep the right contact without pulling.
Then, you need to work on your horse so that he doesn't rush anymore.
You can try to stop him before and after the jump (3sec) and reward him when he does great, help yourself with ground poles before and after the jump that will also help him finding the right stride and don't rush.
Jump only on circles on curves so that your horse doesn't see the obstacle coming and have less time to rush.
Finally, the best thing to do is to work on mechanization lines or bounces.
I hope i could help you :)