Provided is a cellular construction method for an underground connecting channel. The cellular construction method for the underground connecting channel relates to the technical field of civil engineering construction, and the solved technological problem is that an existing method has a high working space requirement. The method divides a target channel into a plurality of channel units; a starting space and a receiving space are arranged at the two ends of the target channel, a plurality of horizontal directional holes are drilled in a soil body between the starting space and the receiving space, and inhaul cables arranged on a horizontal pulling device in the receiving space respectively penetrate through the horizontal directional holes and then are dragged into the starting space; a heading machine nose is pulled by all the inhaul cables, the channel units are tunneled one by one, concrete grout is pressure-injected in a culvert after the construction of all the channel units is completed, and then the concrete grout and the channel units are solidified to form a channel frame duct piece; and the soil body in the channel frame duct piece is excavated out, and then the construction of the target channel is finished. The cellular construction method for the underground connecting channel is particularly suitable for an occasion with a narrow working space.