The invention discloses a heat insulation dairy cow water dispenser. According to the scheme, the heat insulation dairy cow water dispenser comprises a water trough and a support. The water trough is installed on the support. A hot water pipe and a cold water pipe are arranged on the water trough. A water outlet is formed in the bottom of the water trough. A temperature sensor is arranged on the inner wall of the water trough and connected with a controller. The controller controls the hot water pipe and the cold water pipe to be opened or closed. A heat insulation board is hinged to one side wall face of the water trough. A floating ball is arranged below the heat insulation board. An adjusting board is arranged on the edge, stretching out of the water trough, of the heat insulation board. A full water piece and a lack water piece are arranged on the adjusting board. The full water piece is arranged below the lack water piece. The full water piece and the lack water piece are connected with the controller. According to the heat insulation dairy cow water dispenser, water inside the water trough will not lose a large amount of heat in winter, and the water yield is kept stable.