The invention provides a method for sintering and synthesizing powder into porous titanium aluminum intermetallic compound and belongs to the field of synthesis of porous titanium aluminum intermetallic compound. According to the method, titanium powder and aluminum powder are utilized as matrix phase or titanium-aluminum alloy powder is utilized as matrix phase, magnesium powder is utilized as pore forming materials, absolute ethyl alcohol mixed powder is utilized, then the materials are arranged in a mould to be pressurized to form into a green body, and the green body is sintered in the vacuum condition to be cooled along with a furnace. The sintering step is that temperature is raised to 950 DEG C to be kept for 30min, then the temperature is raised to 1150-1350 DEG C to be kept for 2 hours, and the green body is cooled along with the furnace to obtain the porous titanium aluminum intermetallic compound. The porous titanium aluminum intermetallic compound also has a second phase alpha 2 phase in a matrix of a gamma phase. Furthermore, the density of the porous titanium aluminum intermetallic compound is between 1.75 and 2.65g/cm<3>, the porosity is between 26.3% and 51.4%, the yield stress is 1.58 to 150MPa, the compression strength is 1.60 to 204.03MPa, and the elasticity modulus is 0.34 to 6.7GPa.