The electrical and magnetic properties of amorphous CoFeTaBO material were modulated and investigated by controlling the oxygen content of thin films. The resistivity of the prepared CoFeTaBO films increases with the increase of oxygen content, which can be regulated from 10(-3) Omega.cm to insulator. It exhibits good semiconductor properties when the oxygen content is < 43%, and there are mainly two different conduction mechanisms in CoFeTaBO materials, the variable range hopping model in low temperature and the long range interaction between electrons at a relatively high temperature. Meanwhile, the CoFeTaBO films maintain the intrinsic ferromagnetism, exhibiting a Curie temperature higher than 400 K and a coercive field of 40-80 Oe, and they are magnetized to saturation at a lower field in comparison with the oxygen-free CoFeTaB material, which is very meaningful to the application of magnetic semiconductors. The regulation of electrical and magnetic behaviors for ferromagnetic amorphous CoFeTaBO films provides a new way to design and fabricate the novel magnetic semiconductor with desirable properties, probably extending their applications in a wide variety of electronic devices.