Compressive test, splitting tensile test and three point bending test on pre notched beams were carried out for seawater coral aggregate concrete(SCAC) with different strength grades. The fracture parameters such as load crack width relationship, fracture energy and characteristic length were derived. The results show that as the strength grade of SCAC increases, its compressive strength and splitting tensile strength increase, the ratio of tensile compressive strength decreases slightly, the ratio of cracking load to peak load increases significantly, whereas the peak crack mouth opening displacement decreases. It is noted that the cracks of SCAC tend to propagate across the aggregates, thus yielding smooth crack surface. Increasing the strength grade of SCAC can somewhat compensate the low strength features of coral aggregates, resulting in increased fracture energy, but the brittleness raises accordingly.