Aiming at the problem of the low drilling efficiency in pebble stratum,we take three aspects of drilling tool,core-taking and borehole wall protection based on geotechnical investigation of Lae Port project in Papua New Guinea,compare the results of drilling tests using different drilling tool,core-taking methods and borehole wall protection,analyze the reasons affecting the drilling efficiency,and optimize the method.The results show that the main reason affecting the drilling efficiency of the sandy pebble stratum is the secondary problems such as stuck drilling and water leakage caused by the special structure of the pebble stratum.With the plant glue mud and corresponding drilling tool can effectively reduce the occurrence of secondary problems and improve drilling efficiency.