If your dog charges at other dogs on walks, it could be out of either fear or joy -- either way, though, it's unacceptable. If nothing else, it teaches your dog that she, not you, makes the rules. With practice, though, you can show her otherwise and stop her charging.
Allow your dog to socialize with other dogs in a controlled environment. One of the best ways to do this is to set up a play date with another dog or two, so that yours can meet and play with other dogs under your supervision. An improperly socialized dog may be afraid of other dogs because she only sees them as a threat, or conversely, she may charge at other dogs because she is so excited to meet them. In any case, social playing is crucial to her development. When you can, though, choose dogs that are of a like size, as smaller dogs may be intimated and antagonistic to larger dogs.
Practice controlled walking past other dogs. Again, enlist the help of some other dogs and their owners that you know, preferably dogs that are well-behaved on a leash. With your dog on her leash, walk past the other dog on a sidewalk and see how she does. If she charges, restrain her with the leash and correct her using commands that she understands. Of course, if your dog doesn't know any commands like "heel" or "easy," you need to go even further back in her education, and may even consider consulting a professional trainer. You won't be able to stop her from charging if she doesn't know any commands.
Distract your dog when you walk past another dog. Sometimes all a dog needs is something to focus her attention on, so give her something. It can be as simple as waving a stick in front of her face and tossing it, or calling for her to turn around and come back to you to do a trick. Once you're past the other dog, praised her. She'll eventually learn not only to obey your commands, but that passing dogs don't necessarily pose a threat.
Retain control of your dog throughout your walks, not just when you see another dog. Don't let her pull and tug at her leash, and don't let her set the pace of the walk. This requires a whole other training regimen that includes a system of stopping and going in accordance with your dog's walking habits. Once she learns that you control the walk, though, she will be more inclined to defer to your instruction when you come across another dog.
Exude confidence when you pass other dogs. Dogs are receptive to human moods and behaviors, so if you tense up or express concern when you pass another dog, your own dog will pick up on that and may respond with aggression.
Praise your dog consistently every time you pass another dog without her charging. Dogs respond to consistent systems of reward and praise much better than discipline.
Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.