Rousseau's art style is characterized by his bold use of color, flat and simplified forms, and his vivid imagination. He often depicted exotic and dreamlike scenes, such as jungle landscapes, with lush vegetation, wild animals, and mysterious figures. His paintings have a childlike quality and often have a sense of wonder and innocence.

Rousseau's art was not widely accepted by the artistic establishment of his time, but he had a significant influence on the development of modern art, particularly the Surrealist movement. His work continues to be celebrated for its originality and imaginative power.