Abstract: For hard rock-socketed pile tip bearing layer thickness less than 3 times actually, in order to ensure safe and cost savings, base on the analysis of pile-rock and soil system load transfer mechanism and failure mode of rock, we establish the punching capacity formula of pile tip hard-bearing stratum, then use the formula to calculate pile-end hard-bearing stratum anticutting capacity,and it was divided by the pile design load to obtain the of safety K, using the safety factor K to determine whether pile bearing stratum thickness can meet the load requirements. Project examples show: the method in the apply of the red layer region is good and reference.