Defects in the coagulation factor VIII gene cause haemophilia A, which is the most common X-linked recessive bleeding disorder. In total, 45 affected families were investigated to elucidate the factor VIII gene mutation spectrum. The families were subjected to clinical, biochemical, and molecular analyses. Inverse-shifting PCR was first applied to severe haemophilia A patients to identify inversions in introns 22 and 1. Then, next-generation sequencing was performed to detect mutations in inversion-negative patients with severe haemophilia A and moderate–mild haemophilia A patients. Finally, multiplex ligation-dependent probe amplification was utilized to identify rare cases with large fragment duplications or deletions in the factor VIII gene. In total, 41 mutations were identified, 19 of which (c.24C>A, c.49T>C, c.170_171delTT, c.533T>C, c.1126delG, c.1495delA, c.1660A>C, c.1736A>G, c.2711-2712insAATCT, c.3077C>G, c.3846delA, c.4238C>G, c.4349delG, c.4828G>C, c.5821A>C, c.6190C>T, c.6656T>C, c.6902T>G, and c.1904-2A>T) were novel and 80% (44/55) of the pathogenic mutations fell into the categories of missense (43.6%), nonsense (16.36%), frameshift (14.55%), and splice (5.45%) mutations. Additionally, 10 (18.18%) patients displayed inversions in intron 22 or 1 and one case (1.82%) exhibited a 3059-bp large fragment deletion in factor VIII. This study aimed to provide insight contributing to the genetic diagnosis of haemophilia A and to fill gaps in the factor VIII mutation spectrum in northern China.