An adjustable washing rack for an air conditioner contains: a body and a water collection bag. The body includes two opposite supports, a first adjusting rod, and a fixing rod. Each support has a first connecting portion, a rotatable coupling portion, and a second connecting portion. The first adjusting rod is defined between two first connecting portions of the two supports and has a first outer fitting extension and a first inner fitting extension. The fixing rod has a second outer fitting extension and two second inner fitting extensions. The each second inner fitting extension has a first end coupled with a connector for rotatably connecting with the rotatable coupling portion of the each support, and a positioning device is mounted between the connector and the rotatable coupling portion of the each support. The water collection bag includes an opening and a U-shaped surrounding part.