The study selected four types of anti-mildew agents [silver ions, zinc oxide, polyhexamethylguanidine hydrochloride, and copper (Ⅱ) furanoxime complexes], and used a twin-screw extruder to prepare anti-mildew and flame-retardant nylon composites containing nitrogen, bromine, and phosphorus flame retardants, respectively. The study investigated the effects of different types of anti-mildew agents on the flame retardancy and mechanical properties of nylon, and studied the effects of different types of flame retardants on the anti-mildew properties of nylon composites. The results show that the types of anti-mildew agents has no obvious effect on the mechanical properties and flame retardancy of nylon, but has a negative impact on the flame retardancy. Copper (Ⅱ) furanoxime complexes or polyhexamethylguanidine hydrochloride at 0.5% mass fraction can provide good mildew protection, the relevant nylon composite has a mildew protection grade of 0, and the flame-retardant nylon with the same proportion of commercial silver ion or zinc oxide antibacterial agent has only a mildew protection grade of 1. Adding the same content of anti-mildew agent, the nylon composite containing bromine flame retardant and phosphorus flame retardant can reach grade 0, the nylon composite with MCA flame retardant system has the worst anti-mildew properties, and the anti-mildew grade is only grade 3.