The utility model relates to a can be in advance add shearing stress roller compacted concrete water under high pressure splitting test piece the preparation facilities of test piece to solve and only drawn layering spare to the unipolar based on traditional water under high pressure splitting analogue test design device is normal, be difficult to consider shearing stress, and the test piece can only the not enough of normality concrete. The test piece has an extending direction, is equipped with the slope aspect in this extending direction's length direction's middle part position, has a contained angle alpha between this slope aspect and this extending direction, has the crack of presetting in this slope aspect department, should preset the crack through the outside intercommunication of an interface channel and test piece. The preparation facilities forms in the test piece through predetermined mould to have the slope aspect of presetting contained angle alpha and presets the crack. The utility model discloses an influence of the shearing stress of roller compacted concrete aspect can be considered to the test piece to can simulate the work operating mode of the aspect of rolling under the water under high pressure effect of roller compacted concrete high dam more truly, effectively.