Sr2FeMoO6 was synthesized as a visible-light-driven photocatalytic double perovskite by a simple sol-gel preparation method. In-depth experimental techniques were used to characterize morphological and optical properties. Scanning and transmission electron microscopy revealed a tubular shape morphology, resulting in a large active surface area for improved photocatalysis. Optimization of Sr2FeMoO6 achieved a narrow bandgap of 1.77 eV, capable of interacting with visible light. The decomposition of methylene blue (MB) under visible-light irradiation was employed to assess the photocatalytic performance of as-synthesized samples.The Sr2FeMoO6 samples exhibited excellent degradation performance, demonstrating a 95.6% degradation of MB within 35 min of irradiation. This work has certain research significance by revealing the potential mechanism of double perovskite photocatalysts.