The invention relates to the technical field of underground pipe gallery building construction, in particular to a pipe segment splicing method for a segmental prefabricated underground pipe gallery. The pipe segment splicing method comprises the steps that pipe segment parts are conveyed into pipe segment splicing equipment; the pipe segment parts are spliced into an annular pipe segment in the pipe segment splicing equipment; squeezing and pushing acting force is applied to the pipe segment to force the adjacent pipe segment parts to be tightly connected into a whole; then the pipe segment is jacked and pushed to a designed position to be connected with an adjacent pipe segment against the pipe gallery building direction; and the splicing working procedure is completed. The pipe segment splicing mode is convenient to operate, can be widely applied to various open cutting pipe gallery building construction, lowers the pipe segment conveying difficulty, reduces pipe segment conveying cost, improves the pipe segment splicing precision and has great popularization value.