Abstract: A condenser, an air conditioner outdoor unit, and an air-conditioning system. The condenser includes at least one row of heat exchange tubes and a plurality of fins arranged along the heat exchange tubes, where any fin is provided with at least one column of through holes, which correspond to the number of rows of the heat exchange tubes, for the heat exchange tubes to pass through; the fins are evenly divided, in the width direction, into at least one basic unit corresponding to the number of rows of the heat exchange tubes; the width of any basic unit is greater than 18.2 mm; and the center distance between two adjacent through holes from among any column of through holes is less than 21 mm. As a result, the heat exchange efficiency can be improved, and the energy efficiency can also be improved.