The invention discloses a flexible encircling device suitable for reducing rods. The flexible encircling device comprises a drive mechanism, an encircling execution mechanism and a encircling force application mechanism. The encircling execution mechanism comprises a first joint, a second joint, a third joint, a fourth joint, a first joint rotating shaft, a second joint rotating shaft, a third joint rotating shaft and a fourth joint rotating shaft. The encircling force application mechanism comprises a first front push rod shaft, a first rear push rod shaft, a second front push rod shaft, a second rear push rod shaft, a third front push rod shaft, a third rear push rod shaft, a first stress shaft, a second stress shaft, a third stress shaft, a fourth stress shaft, a first force application shaft, a second force application shaft, a third force application shaft, a first front push rod, a second front push rod, a third front push rod, a first rear push rod, a second rear push rod, a third rear push rod, a first telescopic rod, a second telescopic rod and a third telescopic rod. By means of the flexible holding device, the encircling action under multiple reducing conditions such as conical reducing rod pieces, stepped reducing rod pieces and cylindrical rod pieces of different diameter sizes can be completed.