The woman in her 50s was rescued from the boat in Stone, but confirmed dead at the scene.
West Midlands Ambulance Service said the barge was moored on the Trent and Mersey Canal, near the Star Inn pub.
Paramedics were called at about 2.10am this morning.
Firefighters had started CPR when paramedics arrived but the woman died from a cardiac arrest.
Her dog was also confirmed dead at the scene. One ambulance and a paramedic officer attended the scene.
Jamie Arrowsmith, spokesman for the ambulance service, said: “On arrival, crews discovered a woman in cardiac arrest who had been rescued from the boat by the fire service.
“Firefighters had already started CPR which ambulance staff continued.
“However, unfortunately it quickly became apparent nothing could be done to save her and she was confirmed dead at the scene.”