CDA 435C>T is reported as a functional SNP but there is no relevant research on the efficacy/hematological toxicity of gemcitabine-platinum treatment in Chinese non-small-cell lung cancer (NSCLC) patients. In this study, 63 patients who received radical resection (stage IB or IIIA) and 100 advanced NSCLC (stage IIIB or IV) patients have been collected, and all were treated with gemcitabine-platinum regimens from February of 2017 to February 2019. CDA 435C>T polymorphisms have been detected by PCR and direct sequencing. CT scan results and blood routine examinations have been collected to evaluate the efficacy and hematological toxicity. Then the relationships have been analyzed about CDA 435C>T. We found that T allele carriers have better therapy response (p<0.05). Patients carrying CDA 435C/T or T/T genotypes are statistically associated with a better efficacy (p<0.05) but are more prone to leukopenia (p<0.05). Although there is no difference in grade III-IV hematologic toxicity of 163 patients (p>0.05), in the case of 100 stage IIIB-IV patients, the CDA 435C/T and T/T have an increased risk (p<0.05). Regarding the CDA 435C>T polymorphism in the Chinese population, in patients with the mutant T allele, gemcitabine is more effective, but they are more prone to suffering from hematological toxicity, especially the late-stage patients.