The present application discloses a magnetic sensor, fabrication process of perforated integrated circuit module and the magnetic sensor; the magnetic sensor comprises: a head cover, a shaft sleeve, a hollow rotating shaft, a ring alnico, a magnetic sensitive chip matrix, a printed circuit board, a device for output signal and a bottom case; all of them have a through hole except said device for output signal, said magnetic sensitive chip matrix is soldered on said printed circuit board, said device for output signal connects to said printed circuit board electrically, said printed circuit board is mounted below said hollow rotating shaft, and said head cover is mounted on said bottom case to form a cavity, said device for output signal passes out of said cavity. This magnetic sensor can be penetrated by an external shaft and has a thin thickness.