The requirements on ground surface deformation in the construction of Metro in urban areas are strict. The influence of shield boring parameters of Tianjin Station StationJianguodao Station section of Tianjin Metro, such as shield friction, cutterhead torque, working face pressure and grouting pressure, on ground surface settlement is numerically simulated. The risk assessment based on extension method is made on risk failure grade of calculation results of ground surface settlement under different shield boring parameters. The risk failure rate is obtained based on analyzing on the assessment results of risk failure and measured data of shield boring parameters; and then the risk value of every risk factor is calculated and relative fined control technology is proposed. The results show that: 1) The order of risk factors of the test section based on valueatrisk are shield friction, grouting pressure, working face pressure and cutterhead torque. 2) The final ground surface settlement of 5.1 mm can meet the requirements by using fined control technologies.