Chronologically ranged from the Early to Middle Pleistocene, Sus lydekkeri is widely seen in mammalian faunas of the Palearctic and transitional zone of China. More than 20 localities with its remains were reported, but most specimens collected were fragmental and only two nearly complete skulls were described, one from the Middle Pleistocene Peking Man Site at Zhoukoudian in Beijing and another from the Early Pleistocene Yangshuizhan in the Nihewan Basin. The present paper described a third nearly complete and the best-preserved skull of S. lydekkeri so far and other specimens from Jinyuan Cave deposits (paleomagnetically dated 1.1–1.8 Ma) in Dalian, northeastern China. The comparisons of the specimens of S. lydekkeri from different localities show that the intraspecific variation of S. lydekkeri is large and it overlaps with that of S. peii, S. strozzii and S. scrofa in considerable scales. Based on the comparison with available specimens, the most significant difference between S. lydekkeri and S. peii is that the snout of the former is moderately longer than the latter. While the morphological differences between S. lydekkeri and S. strozzii are not very significant. Whereas those between S. lydekkeri and S. scrofa are mostly shown on the canine apparatus, more developed in the former than in the latter. The canine eminence in Sus is a derived character from its Miocene ancestor, evolved into its maximum degree in the Early Pleistocene and reduced gradually in the Late Pleistocene. And that of Dalian skull is the most robust representative among the available specimens of S. lydekkeri. Although the materials are enriched gradually, more complete specimens and larger samples are needed to figure out the clear images of Sus species in face of their puzzling intraspecific variations.