Objective: To investigate the clinical characteristics of small kidney cancer. Methods: The clinical data of 43 patients with small kidney cancer (diameter ≤3 cm) (small kidney cancer group) and 153 patients with kidney cancer (diameter >3 cm) (large kidney cancer group) admitted to our hospital were compared. Results: The clinical stage of small kidney cancer was low, and the difference between the two groups was significant (P < 0.01), and the pathological classification of the two groups was not statistically significant (P > 0.05). The 3-year survival rates of the two groups were 96.3% and 69.8% (P < 0.01), and the 5-year survival rates were 93.8% and 63.6% (P < 0.05), respectively. Conclusion: Small kidney cancer has lower clinical stage than large kidney cancer, better prognosis and higher survival rate, and surgery with preservation of kidney unit is a better choice for the treatment of small kidney cancer.