By the comparison of test results, discussion was made on the effect of variation of subbed soil water content to the test result and suggestion was made to closely protect the test field with 10 mm cement mortar; by the comparison of test results of 2 typical test fields, discussion was made on the possibility of characteristic value of composite ground bearing capacity and suggestion was made to have destructive test, determine ultimate load first and than define the bearing capacity of composite ground by the principle.