NOVELTY - Production of biodiesel comprises adding seed fat and methanol or ethanol into high pressure kettle reactor; then, adding the solid alkali catalyst, magnetically stirring, transesterifying for 1-5 hours under 60-200 degrees C or adding solid alkali catalyst and cosolvent tetrahydrofuran or cyclohexane; after the reaction, filtering while hot, and separating the solid alkali catalyst. The solid alkali catalyst takes zirconia as carrier to load lanthanon oxide or takes zirconia loading thulium oxide as carrier to load the thulium oxide comprising potassium fluoride.    USE - Method for producing biodiesel using zirconia solid alkali catalyst (claimed).    ADVANTAGE - The produced biodiesel using zirconia solid alkali catalyst for transesterification has high catalytic activity. Its post-treatment is convenient and the conversion rate is more than 94%. Reclaimed catalyst can be reused many times and the product biodiesel and its byproduct glycerin are neutral. So, there is no need to wash and no industrial wastewater will be produced.    DETAILED DESCRIPTION - Production of biodiesel by using zirconia solid alkali catalyst, comprises using seed fat as material to react with methanol or ethanol, and adding catalyst to make biodiesel after transesterification. The solid alkali catalyst takes zirconia as carrier to load lanthanon oxide or takes the zirconia loading thulium oxide as the carrier to load the thulium oxide comprising potassium fluoride. The method comprises adding seed fat and methanol or ethanol at a mole ratio of 6:1 to 30:1 into high pressure kettle reactor; then, adding the solid alkali catalyst which is 0.5-5 wt.% of seed fat, magnetically stirring, transesterifying for 1-5 hours under 60-200 degrees C or adding solid alkali catalyst and the cosolvent tetrahydrofuran or cyclohexane which is 5-20 wt.% of seed fat; after the reaction, filtering while hot, separating the solid alkali catalyst; distilling the liquid phase to reclaim the methanol; diverting the liquid phase to tap funnel, and stewing. The superstratum is coarse biodiesel, and the substrate is its byproduct glycerin.