Research purposes: The railway project from Algiers to Oran in Algeria Constracted by China is an important part of road network ringing the Mediterranean Economic Zone in the north part of Algeria，with the total length of 55 km to connects the capital and main industrial areas． The 7． 342 km long Ganntas Tunnel is an important controlling engineering and passes through the low mountain area of Ganntas with complex topographic and geological conditions． Algeria had invited a number of survey institutions from Italy and France to research the geological survey for decades，but little achievements had been made． After winning the bidding by China in 2008，the comprehensive geological survey method was used for the geological survey of this railway by Chinese experienced senior technicians．