The invention belongs to the field of powder titanium alloy materials, and relates to a nano material and titanium alloy composite powder preparing method, in particular to a graphene and titanium alloy composite powder ball milling preparing method. Firstly, an oxidized graphene nano sheet is added in absolute ethyl alcohol, a high-speed mechanical stirrer and an ultrasonic cell pulverizer are adopted for scattering treatment, and an oxidized graphene solution is prepared; then titanium alloy powder and the oxidized graphene solution are arranged in all-direction planet ball milling equipmentto be subjected to controlled-temperature ball milling mixing; then, obtained oxidized graphene and titanium alloy powder muddy liquid is subjected to low-speed continuous stirring till oxidized graphene and titanium alloy composite powder slurry is formed; and after drying treatment, the graphene and titanium alloy composite powder is obtained. By means of the method, good interface bonding is formed between graphene and titanium alloy powder, and dispersibility of the graphene in the titanium alloy powder is greatly improved.