This work deals with the preparation of biocomposites from low-density polyethylene modified by bio-fillers such as fish bones and fish scale and with the study of their dielectric permittivity and dielectric loss depending on the temperature and on the amount of bio-fillers, before and after irradiation with ultraviolet rays. The studies were carried out under the following conditions: a temperature range of 290–390 K. (The dielectrical parameters were carring out before and after UV radiation in temperature range 290–390 K.) UV rays at a dose of 150 Mnit, and duration of 50, 70, 100, and 150 h, in composites with 3, 5, 7, 10, and 15 vol % bio-fillers. The samples were irradiated at room temperature (300 K), with a DRSh-500 lamp. It was found that the dielectric constant of obtained biocomposites during irradiation increases while the dielectric loss decreases. It was revealed that the observed changes in the dielectric constant and in the dielectric loss depending on the temperature and on the volume content of bio-fillers, and UV irradiation time, can be accounted for by a change in the physical structure of the polymer matrix and in the boundary layer of the composition components under the influence of external factors.