Purpose: In this study, zinc oxide nanoparticles synthesized by sol gel and green synthesis method using kombucha tea, which is an inexpensive and efficient method. The use of the obtained ZnO-NPs as a photocatalyst was investigated. The general flow chart of the study is given in Figure A. Theory and Methods: Zinc oxide nanoparticles synthesized by sol gel and green synthesis method using kombucha tea. The obtained ZnO-NPs were used in the photocatalytic degradation experiments of methylene blue, an organic and cationic dye, from aqueous solution under UV lamp. The effects of process parameters on the extent of dye removal, such as photocatalyst quantity, solution pH and MB concentrations Results: According to the results, it is founded that reaction temperature of 60 degrees C and a reaction time of 3 hours were suitable experimental conditions to synthesize ZnO-NPs. The average crystal size of the green synthesized ZnO-NP 22 nm and by sol gel are 89 nm. In addition, it was determined that it has a hexagonal wurtzite crystal structure by XRD analysis. Photodegradation of MB dye with the obtained by green synthesis ZnONP resulted in pH 5, 13 mg/L MM dye concentrations, 0.2 mg/mL photocatalyst at the end of 180 min about 76% dye removal. by solgel ZnO-NP resulted in pH 9, 10 mg/L MM dye concentrations, 0.15 mg/mL photocatalyst at the end of 180 min about 67% dye removal Conclusion: As a result, ZnO-NP was successfully synthesized by both methods. However, by green synthesis is environmentally friendly and easy compared to the chemical method. It was concluded that ZnO-NPs was successful used as photocatalyst.