【Objective】To investigate the tracer effect of carbon nanoparticle suspension in central neck lymph node dissection of differentiated thyroid cancer with other thyroid diseases.【Methods】A total of 500 patients with differentiated thyroid cancer hospitalized in Meizhou People′ s Hospital from July 2015 to July 2019 were retrospectively analyzed. Patients were divided into carbon nanoparticles group（group A，314 cases）and non-carbon nanoparticles group（group B，186 cases）. Group A and B were further divided into 4 subgroups according to the classifications of no other disease （subgroup 0），with nodular goiter（subgroup 1），with Hashimoto′s thyroiditis（subgroup 2）and large tumor（the diameter > 30 mm，subgroup 3），and the number of lymph nodes dissected in each group and the incidence of complications were analyzed.【Results】The number of lymph nodes harvested and metastasis rate in group A was higher than that in group B［6.0（3.0 ~ 9.0）vs. 3.0（1.0 ~ 5.3），P < 0.001；24.4% vs. 20.7%，P = 0.041）］. The number of lymph nodes harvested in group A0，A1 and A2 was higher than that in group B0［8.0（6.0 ~ 11.0）vs. 3.0（2.0 ~ 6.0），P < 0.001）］，B1［4.0（3.0 ~ 6.8）vs. 3.0（0.0 ~ 5.0），P < 0.001）］andB2［8.0（5.0 ~ 12.0）vs. 4.0（0.0 ~ 6.5），P = 0.002］. The number of lymph nodes harvested in group A1 and A3 was significantly lower than that in group A0［4.0（3.0 ~ 6.8）vs. 8.0（6.0 ~ 11.0），P < 0.001；3.0（2.0 ~ 6.0）vs. 8.0（6.0 ~ 11.0），P < 0.001）］. The incidence of hoarseness in group A1，A2 and A3 was comparable with that in group A0（P > 0.05），and the incidence of postoperative parathyroid dysfunction in group A2 and A3 was significantly higher than that in group A0（51.8% vs. 34.1%，P < 0.05；54.2% vs. 34.1%，P < 0.05）.【Conclusions】 The application of carbon nanoparticles in the operation of differentiated thyroid cancer increases the number of lymph nodes harvested，and the best effect is without complicated diseases. The tracking effect of carbon nanoparticles is affect⁃ ed by the combination of nodular goiter. When the maximum diameter of the tumor is greater than 30 mm，it has no obvi⁃ ous effect on the dissection of lymph nodes.