The invention discloses an erbium-ytterbium double-doped lanthanum-lutetium oxide laser material, which is characterized in that it includes the structure shown in formula (I): Er 2x ,Yb 2y :(La 0.1 Lu 0.9‑x‑y ) 2 o 3 (I); wherein, 0.01≤x≤0.09, 0.01≤y≤0.07. The invention discloses a preparation method of an erbium-ytterbium double-doped lanthanum-lutetium oxide laser material, comprising the following steps: step 1, weighing Er 2 o 3 , Yb 2 o 3 , La 2 o 3 、Lu 2 o 3 After dissolving in nitric acid, heat at a constant temperature to obtain a mixed solution, add a combustion agent to the mixed solution, and then add a dispersant, adjust the pH to 7 after it is completely dissolved, continue to heat at a constant temperature and gradually dehydrate to obtain a gel; step 2, the gel Grinding and calcining after drying, and then grinding to obtain nano powder after calcination; step 3, adding sintering aid and absolute ethanol to the nano powder, stirring, drying and grinding to obtain pretreated powder; step 4. After pressing the pretreated powder to obtain a green body, then cold isostatic pressing to obtain a green body; step 5, performing constant temperature vacuum sintering on the green body to obtain the laser material.