With the development of aquaculture, it is an important development direction of fishery engineering to design new types of fiber nets. Polyethylene is widely used in fishery because of its high strength, light weight and cost-effectiveness. However, there are also the problems such as easy to damage for ordinary polyethylene fiber net in aquaculture. Middle high molecular weight polyethylene (MHMWPE) monofilaments have greater molecular weight, higher strength and cost-effectiveness than high density polyethylene (HDPE), which can be prepared by melt-spinning and drawing process. To obtain better mechanical property, we should be willing to modify MHMWPE monofilaments. MHMWPE, isotactic polypropylene (iPP) and ethylene propylene diene monomer (EPDM) were melt blended to spin fishery monofilaments. The effect of the iPP and EPDM contents on the dynamic mechanical behavior and tensile strength of the blending monofilaments was studied by thermal property analysis, dynamic mechanical properties analysis and mechanical properties testing. Results showed that T_g was influenced neither by iPP content nor by EPDM content. The degree of crystallinity and the maximum of loss factor (tanδ_α) for MHMWPE decreased while the temperature of α-transition increased with the increase of iPP content. In addition, the degree of crystallinity decreased, α-transition moved to low temperature and the value of tanδ_α increased with the increase of EPDM content. The stretching strength and knot strength increased by increasing iPP content to a certain value. The toughness and knot strength of the fishery blending monofilaments were further raised by blending of EPDM.