The invention discloses a test system and method for natural dirt retention characteristics of a single insulator. The test system for the natural dirt retention characteristics of the single insulator comprises a photovoltaic energy storage module (1), a high-voltage generation module (2), an environment parameter measuring module (3) and an insulator module (4), wherein the photovoltaic energy storage module (1) provides power; the high-voltage generation module (2) is used for providing alternating-current voltage and direct-current voltage; the environment parameter measuring module (3) is used for measuring environment parameters; the high-voltage generation module (2) comprises a power frequency inverter (11), a first boosting transformer (12), a second boosting transformer (22) and a rectifier module (13); the first boosting transformer (12) is connected with the power frequency inverter (11) and generates the alternating-current voltage; the second boosting transformer (22) is connected with the power frequency inverter (11); the rectifier module (13) generates the direct-current voltage; the insulator module (4) comprises a fixed base (14) and an insulator frame (15) which is arranged on the fixed base (14) and is used for supporting an insulator string; and insulators (16) in the insulator string are electrically connected with the high-voltage generation module (2).