The present invention discloses a portable cyclone dust separator, which comprises a first stage cyclone separation unit having an intake for suctioning air to be dedusted, the air suctioned through the intake rotating around a first rotational axis in the first stage cyclone separation unit; and a second stage cyclone separation unit having an air inlet, the air inlet being configured to be adapted to suction the air, which needs to be dedusted secondarily by the second stage cyclone separation unit, from the first stage cyclone separation unit, the air suctioned through the air inlet rotating around at least one second rotational axis in the second stage cyclone separation unit, wherein the first rotational axis is disposed to be nonparallel to the second rotational axis. The present invention also discloses a dedusting system comprising such a portable cyclone dust separator. The portable cyclone dust separator of the present invention is fit for the operating orientations within the greater angular range.