The prevention of nuclear radiation-induced biological damage belongs to the cross field of protective materials and cell biology. It is a long-standing and urgent challenge to enhance the protective ability of new materials so as to reduce their biological damage caused by nuclear radiation. In this work, on the premise that the total content and type of filler are consistent, a series of flexible composites with alternating layered distribution of Tungsten boride (WB2)/poly(ethylene-co-1-octene) (POE) and Bismuth (Bi)/POE are innovatively manufactured. POE and shielding fillers (including WB2 and Bi) have excellent shielding effects on neutrons and gamma rays respectively, and the introduction of a multilayer structure can make the rays scatter and absorb multiple times at the layer interface. The multilayered composites achieve more than 90% shielding efficiency for gamma rays at below 120 KeV energy level. Simultaneously, its neutron shielding efficiency also exceeds 80%. Importantly, the protective effect of these multilayered composites on the biological damage triggered by nuclear radiation is also studied thoroughly. Amazingly, our composites significantly alleviate the pathological injuries induced by 1.0 Gy irradiation of 60Co-γ rays, which are demonstrated by histopathological changes in sensitive organs, the levels of hemocytes and DNA damage marker. Besides, compared to no detectable changes of abovementioned conventional biological detections, the methylation levels of the sex chromosome of the organism can efficiently indicate the biological effect of low-dose radiation on the organism, and the multilayered composites can protect mice from chromosome methylation alteration. This work not only provides a multilayered composite with excellent shielding efficiency and bioprotective performance for nuclear radiation but also finds an accurate detecting method for radiation damage even caused by low-dose radiation.