The invention discloses an automatic machine for preparing cocktail, comprising a framework, a tank disposed on the framework, a pipeline connecting the tank and a cocktail outlet, and a programmable controller, which is characterized in that the tank communicates with a liquor inlet of a multi-channel switch device through a first division pipeline system, a liquor outlet of the multi-channel switch device communicates with a liquor inlet of a meter pump through a second division pipeline system, a liquor outlet of the meter pump communicates with the cocktail outlet, and the multi-channel switch device and the drive portion of the meter pump communicate with the programmable device. The invention is provided with the advantages that more than one thousand of cocktail formulas can be memorized in the programmable controller; the cocktail is prepared quickly, thus enhancing efficiency and benefit; the plug meter pump needing no one-way valve is provided with accurate extraction volume and precise preparation; and the whole device is provided with advanced structure and convenient use, thereby realizing automatization and mechanization for preparing cocktail.