The filling of joints in rocks affects the stability of the rocks, and understanding the effect of filled joints on the fracture properties of rocks is of great importance in practical engineering. In this study, mechanical tests were conducted using cracked straight-through Brazilian disc (CSTBD) gabbro samples with different fracture dip angles with and without fissure filling cement. The results showed that the fracture load of CSTBD gabbro specimens with different crack inclination angles, β, increased slightly after cement-filling central fissure, with a maximum increase of 12.78 % at a β of 90°. Compared with unfilled specimens, the fracture characteristics of the specimens were less affected by nodal cement filling, which only prevented the lateral expansion of cracks at β of 90°. The crack inclination angle also controlled the fracture mode of the specimen. With increasing crack inclination, the crack initiation angle increased, and the fracture load of the specimen first decreased and then increased. The crack extension also gradually changed from open to closed mode with increasing crack inclination. Under compression, stress within specimens not filled with cement is predominantly concentrated at the crack tip. Conversely, specimens with cement-filling display stress concentration across the entire prefabricated crack and at the interface with the cement. The cement filling markedly diminishes the stress concentration in the specimens, which in turn strengthens the rock’s ability to resist deformation. The results of the study provide theoretical guidance for assessing the fracture characteristics of joint-filled rocks.