In order to study the crystallization behavior and properties of PA66 modified by different kinds of semi-aromatic copolymerized nylon resin, different kinds of semi-aromatic copolymerized nylon resin were added to PA66 resin, and the effects of different kinds and contents of semi-aromatic copolymerized nylon resin on the crystallization behavior and properties of alloy mate‐ rials were studied. The results show that different kinds of semi-aromatic copolymerized nylon resins have different crystallization behavior and optimal content in the blends. With the increase of poly-m-xylyleneadipamide (MXD6) content, the melting temperature (T_m) and crystallization temperature (T_c) of the blend decrease, the rigidity and thermal deformation of the blend increase, the m c toughness and the water absorption decrease, and the density has little effect. When the addition amount of polyphthalamide(PA6T/6) is greater than or equal to 40% of the resin component, the crystallization behavior of the blend starts to change significantly, the rigidity and thermal deformation of the blend are enhanced, and the toughness is reduced. With the increase of PA6T/6 content, the water absorption of the blend decrease, and the density has little effect. When the added amount of poly(p-phenyl-pentadiamine) (PA5T) is greater than or equal to 30% of the resin component, PA5T starts to play a role in the blend, the toughness is reduced, the water absorption is reduced. The water absorption of the blend first decreases and then increases with the increase of PA5T content, and the addition amount of PA5T has little effect on the density of the blend. When the amount of polydecamethylene terephthalate (PA10T) is less than 40% of the resin component, the T_m and T_c of the blend gradually decrease, the rigidity and thermal deformation m c of the blend are enhanced, and the toughness is reduced. The water absorption of the blend decrease with the increase of PA10T content. When it is increased to 50% of the resin component, the water absorption is no longer reduced, and the rigidity and thermal deformation are no longer enhanced.