The present application discloses a grouting consolidation sample containing internal defects and the preparation method thereof. Firstly, plasticine is employed to prepare a wax model with the desired defect shape, then a fixing device is used to fix the wax model onto a specific position in a casting mould of consolidation and thereafter a slurry is poured to form a grouting consolidation sample, after the grouting consolidation sample reaches the predetermined strength, the grouting consolidation sample containing the wax model is put into an oven to heat at a temperature above the melting point of wax to demolish the structure of the wax model to form a grouting consolidation sample with internal defects.