The invention discloses a portable power source type track laying machine for subway construction. The track laying machine comprises a door type support, a lifting device, a traveling device and a portable power source, wherein the lifting device is installed on the door-type support, the traveling device is used for driving the door type support to move forwards and backwards, and the portable power source is installed on the door type support or the traveling device. The door type support comprises a main beam and two height-adjusting supporting legs, wherein the two height-adjusting supporting legs are installed on the lower portions of the two sides of the main beam respectively; the main beam comprises a straight beam body and telescopic beam bodies, wherein the telescopic beam bodies are connected to the left end and the right end of the straight beam body in an inserted mode respectively. Each telescopic beam body is provided with an inserting connection end and a fixed end, the inserting connection ends of the telescopic beam bodies are installed in the straight beam body, and the fixed ends of the telescopic beam bodies are fixedly installed on the tops of the height-adjusting supporting legs. In the portable power source type track laying machine, the portable power source is used as a power source of the laid track, in the long and large section laying process, it is only required that the portable power source is changed, it is not required that power supply interfaces are changed many times, and coiling cables do not need to be deployed and retracted frequently, the manpower, machines and tools, materials and time cost required for laying and constructing the power source are saved.