Experiment on cryogenic abrasive air jet machining (CAAJM) of PDMS has been achieved using self-developed CAAJM device. Based on the experimental study of CAAJM of PDMS, the influences of machining time, the centerline distances from the nozzle to the target, attack angle and the diameter of abrasive on erosion rate, the depth of holes and cross-sectional morphologies are investigated. Results indicate that with the increase of time, erosion rate firstly increases and then decreases. In the first stage of processing, the depth of the hole has linear relation to the the machining time. Increasing machining time can make the bottom of the hole smooth. There is an optimum distance to get the maximum machining depth. When the machining distance is greater than the optimum distance, the depth of the hole drops off sharply with machining distance. The taper of the hole grows with machining distance. The maximum erosion rate can be obtained when attack angle is between 30°and 60°. With the increase of attack angle, the shape of the hole gradually changes from elliptical to circular. There is an optimum diameter of abrasive to get the maximum erosion rate and machining depth. When the attack angle is less than 90°, the material removal mechanism of CAAJM of PDMS is a mix of ductile erosive system and brittle erosive system.