A dog that needs leash training could benefit from the use of a training lead. This is a short leash that keeps the dog at your side. This kind of leash will let you correct bad behavior quickly and effectively by redirecting the dog away from distractions. A shock collar, choke chain, or prong collar has no place in retraining. While it might seem tempting to use a prong collar or choke chain, these work by inflicting pain and having the dog associate pain with pulling. Not only could these devices cause actual physical harm to the dog, but they work using fear rather than helping the dog to learn in a positive way. In addition, these collars are generally the mark of an inadequate trainer who doesn't know how to correct such behavior in any other way. Don't let this be a label applied to you, but instead retrain your dog in a humane manner using canine psychology. The chances are the dog is beside itself with excitement as soon as the leash appears. This is because it associates the leash with a walk. You want your pup to be calm when you set off, so that you are more likely to succeed in retraining.  To this end, clip the leash on and off the dog in the house, but without going for a walk. Your aim is to break the assumption that because the dog has a lead on it is going for a walk.  For example, when you are home, clip the leash on but go about your normal routine in the house. After 5 - 10 minutes, unclip the leash and carry on as usual again. Repeat this every half hour or so, so the dog becomes desensitized to wearing the leash.

TL;DR in Vietnamese:
Chọn đúng loại dây. Tránh áp dụng những biện pháp huấn luyện trừng phạt. Giảm bớt sự phấn khích của chó với việc đeo xích.