The invention discloses a brittle core and irregular core clamping device and a core drilling method thereof. The brittle core and irregular core clamping device comprises a rack, a left clamping module, a right clamping module and a crank; the left clamping module and the right clamping module are located on the left side and the right side of the rack separately; the left clamping module moves left and right on the rack under the action of the crank; the right clamping module is fixedly arranged on the rack; the crank is located on the left side of the rack; and the inner end portion of thecrank is fixed to the outer end portion of the left clamping module to achieve left-and-right movement of the left clamping module. Core drilling and coring work of brittle cores and irregular cores can be achieved, so that the cores are not prone to being broken or shifting in the drilling process, and the success rate of a drilling plunger is increased; useful first-hand information is providedfor various later experiments; and the blank that the brittle cores and the irregular cores are difficult to drill is filled up.