This research paper presents constitutive parameters of poisonous marine invaders (Diadema setosum) for microwave application. Two different powder form of these invaders were prepared and calcined at different temperatures. These biomaterials have been obtained for grinding shell and spines of sea urchin were turned into powder. Constitutive parameters of these classified biomaterials have been investigated in 3.2-20GHz frequency range with open-ended coaxial probe method. Measured results show that these biomaterials have a potential usage area in microwave range are mentioned firstly in literature. Measured complex permittivity properties of samples of shell and spines of invasive long-spined sea urchin have demonstrated that samples can be utilized in development of high-quality microwave radomes with high impedance matching to air and low loss microwave substrates.