The invention discloses a preparation method of a silicon-aluminum sputtering target material high in density, low in oxygen content and not prone to embrittlement. The preparation method comprises the following steps of target material base tube preparing, wherein a stainless steel base tube of the required type is selected and checked; base tube surface pretreatment, wherein the base tube is made to enter base tube pretreatment equipment to be subjected to sand-blasting roughening, a nickel-aluminum alloy wire is utilized, a bottoming combination layer is sprayed through an arc spray method, and a target material base tube to be sprayed is obtained; raw material preparing, wherein 50 kg of silicon powder with the content ranging from 99.9% to 99.95%, the oxygen content being smaller than or equal to 1,000 ppm and the particle size ranging from 45 micrometers to 150 micrometers and 6.6 kg of high-purity spherical aluminum powder with the content ranging from 99.9% to 99.95%, the oxygen content being smaller than or equal to 1,500 ppm and the particle size ranging from 45 micrometers to 100 micrometers are weighed; powder mixing, wherein two obtained raw materials are put into a V-shaped powder mixer to be mixed for 5 hours to 6 hours; and drying, wherein an evenly-mixed silicon-aluminum powder raw material is put in a drying furnace to be dried for 2 hours to 3 hours, and the temperature is 60 DEG C.