In this paper, the effects of fibre content on the interlaminar fracture in continuous glass-fibre/polyamide 12 composite have been investigated under model I (DCB) loading condition. The specimens were fabricated with different fibre volume contents (21%, 26%, 34% and 39%) by using a powder impregnation method. It was observed that the values of GIC(NL) and GIC(PROP) of this material have a dropping tendency with increasing fibre volume content in the range of 21%–39%, while no general trends in GIC(5%) and GIC(VIS). Results show that the glass-fibre/polyamide 12 composites possess high mode I fracture toughness, which is mainly attributed to the high ductility of the polyamide 12 matrix, and the increased fibre bridging caused by the increasing of the fibre volume content can not change the decrease tendency of GIC(PROP). The fracture surfaces of the specimens were observed by scanning electron microscopy, and the fracture mechanism was analysed.