Objective To observe the changes of tumor markers and CT imaging before and after chemotherapy of lung adenocarcinoma. Methods 56 cases of patients with lung adenocarcinoma who admitted in our hospital between May 2012 and April 2015 were included into the study. All patients were treated with chemotherapy. The serum tumor markers such as alpha-fetal protein (AFP), carcino-embryonic antigen (CEA), carbohydrate antigen (CA125, CA199, CA153) which determined by chemiluminescence method were recorded before and after chemotherapy. Meanwhile, pulmonary CT imaging examination was performed. The changes of tumor markers and CT imaging before and after chemotherapy of lung adenocarcinoma were analyzed. Results After 4 cycles of chemotherapy, the serum tumor markers such as AFP, CEA, CA125, CA199 and CA153 decreased significantly. Compared with those before chemotherapy, there were statistically significant differences (P<0.05), after 4 cycles of chemotherapy, there were 8 cases completely remitted, 28 cases partially remitted, 18 cases stable and 2 cases in progression. There were a total of 36 cases (64.29%) effective and 20 cases (35.71%) in progression. Levels of tumor markers such as AFP, CEA, CA125, CA199 and CA153 in effective group were significantly lower than those in the progression group (P<0.05). Conclusion After chemotherapy, the changes of serum tumor markers and CT imaging in patients with lung adenocarcinoma were relatively higher consistency. For some patients whom CT examination cannot evaluate, serum tumor marker can be used to help examination, so as to provide guidance for the adjustment of treatment.