The utility model discloses a drum type permanent magnet coupling belongs to magnetic eddy current transmission forever, including driving shaft (3), initiative end (1), driven end (2), driven shaft (4), driving shaft (3) are driven by the motor, drum type conductor on the initiative end (1) corresponds the setting with the permanent magnet on driven end (2) the drum gappedly, driving shaft (3) tip is furnished with sliding shaft (31), sliding shaft (31) can endwise slip in the limited range with initiative end (1) fixed connection, static sliding seat (5) are fixed in on the equipment occasionally together, wherein slip cap (7) and fix and dispose bearing (6) between bearing frame (8) on sliding shaft (31). The utility model discloses (1) and the function of driven end (2) interval in the preset range are held in convenient adjustment initiative in having the working process, and this kind of drum type permanent magnet coupling price is relatively low, and the installation operation is simple and convenient relatively.