Abstract According to the data of static loading test and dynamic high strain test of pile in Xining city,the bearing properties and loading transmission mechanism of the large-diameter and medium-long borehole cast-in-place piles in muddy rock foundation,as well as the influencing factors on its bearing properties are revealed by analyzing pile axis pressure transmission and soil resistance properties. The study result is instructive for design,construct and deep study of borehole cast-in-place piles in muddy rock foundation.