When choosing a guard dog, it is very important to ensure that it will not bite randomly. The following are some recommended dog breeds and training suggestions:

1. Labrador Retriever: Generally considered a friendly family pet, it can also be trained to become an excellent guard dog, and it is not easy to May bite randomly.

2. German Shepherd: Intelligent, loyal and easy to train, the German Shepherd can vigilantly protect the family, but usually only takes action when necessary.

3. Golden Retriever: docile, friendly, and can also play the role of housekeeper. Family members and guests are very welcoming.

In addition, in order to ensure that dogs will not bite people, effective training is key. During the training process, defensive reflexes and attachment can be used to cultivate the dog's alertness to strangers, and at the same time, it can learn to bark appropriately under the command of the dog owner, rather than attacking directly. During training, the safety of your dog should always be ensured and avoid overstimulating or injuring them.