Heavy metal pollution was observed in rivers, lakes, and other aquatic environments that damaged the aquatic ecosystem and indirectly threatened human health. To explore the ecotoxicology of heavy metal on aquatic insect Chironomus kiiensis, the pupation rate, emergence rate, teratogenic of the mouthparts and enrichment effects of C. kiiensis were measured under Cd²⁺ and Pb²⁺ stresses. The results showed that both Cd²⁺ and Pb²⁺ affected pupation and emergence of C. kiiensis larvae. The pupation rate and emergence rate of the C. kiiensis larvae treated by Pb²⁺ were 22.22% and 8.89%, which was lower than that of larvae treated by Cd²⁺ with 25.56% and 11.11% for 14 d stress, respectively, showing a higher inhibitory effect. The pupation rate and emergence rate of C. kiiensis larvae treated by 1:2 and 2:1 of Cd²⁺ and Pb²⁺ were all 11.11% and 4.44%, respectively, which was significantly lower than those of single heavy metal stress. The treatments of single and mixed heavy metals could lead to teratogenicity of mouthparts in C. kiiensis larvae, manifesting as the apical teeth of mandible fracture, middle teeth, basal teeth wear and loss, mentum irregular, marginal teeth and central teeth of the mentum wear, fracture, hyperplasia, and loss. The mouthpart teratogenicity rates of C. kiiensis larvae varied with the treatment of different heavy metal ions and showed a positive correlation with the exposure time. Among different treatments, the teratogenic rate of C. kiiensis larvae treated by 1:2 of Cd²⁺ and Pb²⁺ reached 40.61%. Moreover, heavy metal ions produced bioaccumulation effects in C. kiiensis larvae. Exposed for 7 d to 14 d, the concentration of Pb²⁺ in C. kiiensis larvae increased from 11.46 mg/kg to 31.32 mg/kg. The Pb²⁺ concentration in C. kiiensis larvae treated by the different mixed ions showed an increasing trend, and the Pb²⁺ concentration in C. kiiensis larvae treated by 1:2 mixed ion treatment ranged from 15.48 mg/kg to 42.50 mg/kg. However, the concentration of Cd²⁺ in C. kiiensis larvae treated by the single heavy metal and 1:1 mixed ion treatment from 7 d to 14 d had no significant difference. The Cd²⁺ concentration in C. kiiensis larvae treated by 2:1 mixed ion treatment group decreased from 14.20 mg/kg to 9.52 mg/kg, whereas that in 1:2 mixed ion treatment group increased from 5.85 mg/kg to 20.99 mg/kg. The results indicated that Cd²⁺ and Pb²⁺ could inhibit the growth and development and produce mouthpart teratogenicity of C. kiiensis larvae, which was closely related to the accumulation of heavy metals in C. kiiensis larvae. These results provided a theoretical basis for the multiple effects of heavy metals on the aquatic ecosystem.