Abstract: The specific problem of physical strength testing of cement-soil mixing piles is discussed. It is pointed out that the physical quality test of the compressive strength of cement-soil mixing piles and the strength test of indoor cubic standard specimens are not uniform. The strength relationship between specimens of different sizes is unclear and lacks the basis for use. The relationship between the unconfined compressive strength of cement-soil with different sizes and shapes is analyzed through experimental research. It is feasibe to directly evaluate the strength using the test results with cylindrical core samples, and the key issues need attention during the process of obtaining core samples is pointed out also, all of which discussed maybe contribute practical and guiding significance.