Abstract: Along the Fujian-Guangdong region there are in general 3 sets of tectonic lines. The most striking ones, belonging to the NE-trending Neocathaysian system, represent the principal ranges and valleys. The Ew-trending lines are lesser in number. The Nw-trending ones, poorly known and represented often by fractures, will be briefly discussed in this paper.The NW-trending fractures are numerous in Southeast China, particularly in the coastal areas of Fujian, Guangdong and Guangxi provinces. They are equidistantly apart in a regular pattern, many of them are followed by rivers; some may measure be comparable in size with the Neocathaysian fracture; most of them are vigorously active in recent geological periods.A thorough investigation into the NW-trending fractures may be significant in solving (l)some geological problems not yet resolved theoretically, as well as those frequently met in Southeast China and (2)some practival problems regarding ore searching, delta conservancy and earthquake predition.