There are a few different tactics that will correct this behavior:

• The first and easiest thing to try is using a bitter apple liquid. Liberally apply the bitter apple to the entire length of the leash. It may be a bit messy and will smell awful but it is worth it. Some dogs do actually like the taste of this product so as an alternative try using the hottest sauce that you can find. Neither of these methods will harm your dog, but most dogs only need try this a few times before they realize that it does not taste good.
• Another simple technique is the moment that your dog begins biting the leash, Stop. Give him a sharp “no” and remove the leash from the dog’s mouth with a quick pull. You may have to repeat this a few times before it works.
• If you have begun training your dog with the leave it command this is a great time to practice. If your dog drops the leash, give him a reward. However, be wary, you do not want the dog learning that he will be rewarded for taking the leash.
• You might also try the stop walking method during your dog leash training exercises. The moment the dog starts to bite his leash STOP and freeze. Do not move, this is the same technique that you can use to get your dog to stop pulling. Once your dog settles down, begin moving again. Your dog will get the idea that nobody goes anywhere when the leash is being bitten. You might even try putting the leash under your foot and ignoring your animal until he calms down. Once the dog is quiet and calm continue walking.
• If your dog is very playful, he may be biting the leash for more attention. You could try allowing the dog to carry a toy, ball or stick on your walk.
• Another idea is to try getting your dog to focus on other things while you are walking. Make the walk more challenging. Change your direction frequently; this will help to keep the dog’s attention off the leash. You might also try issuing other commands as well such as working on sit and stay. It may take a bit longer to get where you are going but it works.
• Take the dog somewhere new. Try walking your dog in different places. If a dog is entertained by new sights and sounds he is too busy to bite the leash.
• If need be, shorten the leash as much as possible. Keep the dog in almost, the heel position and begin walking. Walk at a very brisk pace. Do not talk to your dog, or pet him, keep moving.

With patience and practice you can get your dog to stop biting the leash. But you have to remain consistent. Whichever method you decide to use, be sure to give it time to work. None of these will work the first time out; they might not even work the second, but keep at it. You and your dog will reap the rewards.