This study aimed to evaluate camphor tree ash (green biomass ash) supported K2CO3 as a solid base catalyst for biodiesel production. The catalyst was prepared by way of first-calcination, K2CO3 solution impregnation, and second-calcination method. The catalytic performance of the catalyst for the preparation of biodiesel was investigated. Under the optimal conditions of K2CO3 loading of 50 wt%, first-calcination temperature of 800 degrees C, second-calcination temperature of 500 degrees C, catalyst concentration of 5 wt%, catalytic time of 210 min, methanol/oil molar ratio of 14:1, and catalytic temperature of 65 degrees C, the biodiesel yield reached 92.27%.