The invention relates to a color-selecting mechanism of a weaving and proofing machine, and belongs to the textile machinery. The color-selecting mechanism comprises a color-selecting device, a driver and a driving device, wherein the color-selecting device is arranged on one side edge of the weaving and proofing machine, and is symmetrically provided with a group of color-selecting disks, each of which is provided with a plurality of orderly arranged vertical punch holes; and weft threads with different colors are respectively arranged in the punch holes; the driver is arranged on the color-selecting disks, and is connected with a stepping motor, so the stepping motor can drive the color-selecting device to rotate; the driving device is arranged on the upper side corresponding to the outlet side of the color-selecting disks, and the power output terminal of the driving device is connected with a push rod, so the driving device can drive the push rod to do the up-and-down reciprocating motion. The color-selecting mechanism has the advantages that a motor is utilized for driving, so as to enable the proofing machine to be fast and accurate when the colors of the weft threads are selected, no noise is produced and the practicability is strong.