Abstract: Disclosed is an ash-collecting pan and ventilation adjusting device for a barbecue set, of which the bottom of the body portion is formed into a flat bottom with a plurality of through holes provided for ash dropping and ventilation functions. On the outer circumference of the flat bottom, three L-shaped flange plates are provided for mounting the ash-collecting pan under the barbecue set. The ash-collecting pan comprises two rested pans, including an inner pan and an outer pan at a suitable height. The walls of each of the two pans are furnished with several corresponding ventilation apertures. The bottom of the inner pan has a handle attached thereto and extending under the outer pan. The inner pan can be turned by means of the handle so as to vary the size of the corresponding apertures between the two pans, whereby the air supply to the barbecue set may be adjusted. Further, the handle can facilitate insertion and removal of the ash-collecting pan from the barbecue set.