In order to solve the technical difficulties in the development of the first quasirectangular shield tunnel in urban soft soil in China, the determination of technical standards and grades, key and difficult points of investigation, investigation program, geological characteristics of high rheological and soft soil, hydrogeological conditions of construction site and suggestions on construction technology are analyzed. Some conclusions are drawn as follows: 1) The complexity grade of construction site in soft soil and the depth of investigation drilledhole of quasirectangular shield tunnel of relevant standards and criteria are conservative, which will definitely lead to work waste. 2) The investigation drilled holes with depths of 2H to 3H, where H is tunnel height, under tunnel bottom are rational and economical when quasirectangular shield tunnel is located in Quaternary marine sedimentary soft soil area. The investigation program abovementioned can provide reference for the future revision of engineering investigation of quasirectangular shield tunnel and relevant standards.