The invention discloses an automatic drinking water vehicle for cows, which comprises a drinking tank, a locomotive main body, a moving device, a water storage tank, a water tank cover, a floating ball, a fixed pulley, a water outlet valve, a solar battery panel, a battery panel bracket, a spring, a storage battery, Sterilizer and heating rod, the water tank is fixedly connected to the locomotive body, the locomotive body is rollingly connected to the mobile device, and the upper side of the locomotive body is fixedly connected to the water storage tank, and the upper side of the water storage tank is hinged to the water tank cover , a floating ball is installed inside the water tank, the right side of the water outlet valve is connected to the spring, the right side of the water storage tank is connected to the solar panel through the battery panel bracket, and the upper side of the main body of the locomotive is fixedly connected to the battery. The inside of the water storage tank is fixedly connected with the heating rod, and the inside of the water tank is fixedly connected with the heating rod. This device uses solar energy for power generation and functions, which is energy-saving, pollution-free, green and environmentally friendly. At the same time, it can realize automatic water addition without manual operation, saving manpower.