Disclosed is a tent frame, a unit tent and an extendable cubic tent group. The tent group is assembled from a plurality of unit tents sharing edge structures. The unit tent consists of an inflatable tarpaulin and a tent frame. The tent frame includes bases, columns and beams. The beam is provided with at least a first water channel and a second water channel in a length direction. The present invention is simplified in the structures of the columns and the beams, which is more beneficial to coping with the situation of large water volume. Besides, the assembly of small parts can be reduced, and the stability of the structure can be enhanced, so that the structural weight of the overall frame is greatly reduced while the hidden water discharge function is reserved.