A method for preparing a porous tantalum medical implant material, which includes (a) mixing a polyethylene glycol aqueous solution and tantalum powder to form a tantalum slurry, (b) casting the tantalum slurry into an organic foam body through vibrant pressurization, and (c) performing steps of drying, degreasing, vacuum sintering and thermal treatment to obtain the porous tantalum. The solution is a 2-8 wt % polyethylene glycol aqueous solution, the frequency of vibration is 20-80 times/min, the thermal treatment is performed under 10−4-10−3 Pa of vacuity and the temperature is first increased to 800-900° C. at a rate of 10-20° C./min and kept at 800-900° C. for 240-480 minutes, then is decreased to 400° C. at a rate of 2-5° C./min and kept at 400° C. for 120-300 minutes, and is cooled down to room temperature naturally in the furnace.