Cross－cut tests on several Portland cement samples are made on the base of five parameters (cement fineness, SO₃ content,  K₂CO₃ content, additive addition ratio with hemihydrate gypsum and dihydrate gypsum). Through ascertain the past fluidity, the compatibility of cement and water reducer under different parameters and different levels were investigated.

    Thus optimal combination and influence factors are obtained. This verified that the cross－cut test is a feasible method to study the compatability of cement and water reducer.