A portable air pump includes an inflation assembly, a head seat pivotally connected to the inflation assembly, a pressure gauge disposed in the head seat, a connection assembly pivotally connected to the inflation assembly, and an axial member. The inflation assembly includes a cylinder and a piston rod moveable relative to the cylinder to compress the air inside the cylinder. One end of the head seat is provided with the containing groove, and another end of the head seat is provided with a pedal portion. The connection assembly is adapted to connect with an air-inflatable object. The axial member is mounted through the inflation assembly and the head seat and is connected to the connection assembly. The axial member is provided with an airflow channel communicating with the cylinder, the containing groove, and the connection assembly.