The present invention discloses a sampling device for an ion migration spectrometer (IMS), comprising: an inner sleeve part, inside of which an inner cavity is defined, one end of the inner sleeve part is connected with an inlet of an migration pipe via an inner-layer channel, and the other end of the inner sleeve part is configured with an inner end cap having an inner opening; and an outer sleeve part, which is configured as an eccentric sleeve that is coaxial with the inner sleeve part and able to rotate with respect to the inner sleeve part, so as to form a sleeve cavity between the inner sleeve part and the outer sleeve part, wherein one end of the outer sleeve part is configured with at least one connecting opening that is selectively connected with the inner-layer channel, and the other end of the outer sleeve part is configured with an outer end cap, on which a first outer opening selectively connected with the inner opening and a second outer opening selectively connected with the sleeve cavity are configured, wherein the outer end cap is configured to be able to rotate between a first location and a second location with respect to the inner end cap, so as to selectively introduce a sample to be detected into the inner-layer channel via one of the inner cavity and the sleeve cavity. Moreover, the present invention further relates to a method for solid and gas sampling by using the above sampling device.