Objective To study the changes of vitamin levels in patients with esophageal cancer during chemotherapy. Method The clinical data of 243 patients with esophageal cancer who received chemotherapy in the No.910 Hospital of PLA from July 2017 to September 2020 were selected. The levels of nine vitamins[A，B1，B2，B6，B9(folic acid)，B12，C，D，E], hematological indexes and body mass index (BMI) in patients with esophageal cancer were measured before and after two cycles of chemotherapy. The changes of the number and average level of 9 vitamin deficiency patients in patients with esophageal cancer after two cycles of chemotherapy were compared. Pearson correlation score was used to analyze the correlation between the differences of various vitamin levels and the changes of BMI before and after chemotherapy. Result the age of 243 patients ranged from 39 to 76 years, with an average of (60.14 ± 8.26) years. The main stages of esophageal cancer were stage Ⅲ 117 cases (48.15%) and stage Ⅳ 80 cases (32.92%). The level of vitamin A, B2, C and D in patients with esophageal cancer before initial treatment was lower than the normal value (P < 0.05). After 2 cycles of chemotherapy, the levels of vitamin A, B2, B6 and C decreased significantly (P < 0.05). After two cycles of chemotherapy, the levels of hemoglobin, total protein, serum albumin and blood calcium decreased，and the level of blood phosphorus increased significantly (P< 0.05). The changes of blood vitamin A (r=0.343，P<0.001) and C (r=0.388，P<0.001)were positively correlated with the changes of BMI. Conclusion There are vitamin A, B2, C and D deficiencies in patients with esophageal cancer receiving chemotherapy.