A control method of an electrical thermostat that includes an operating heater heating wax so as to operate an operating valve that may be disposed to close a coolant passage according to an exemplary embodiment of may include detecting a coolant temperature of coolant circulating a coolant passage, determining whether the coolant temperature may be included in a predetermined heating temperature range, performing a coolant heating mode by supplying a predetermined level of power to the operating heater for a predetermined time, if the coolant temperature may be within the heating temperature range, and stopping the coolant heating mode in a condition that the operating valve may be closed.