Blood in your dogs urine is not normal and is usually caused by infections within the dogs Urinary Tract which should be checked out by a Vet.
Blood in the dogs urine could be caused by urinary crystals or urinary stones or simply a bacterial infection.
Either way a vet needs to see the dog to treat him/her.
The vet will likely prescribe some antibiotics that you give your dog to treat the infection of the Urinary Tract.