Facing the vast market of China urban underground space development and utilization in 2 1 century, during 2000-2009 10, more than 20 cities in China will build subways with at least 250km. Using shield machine will be an inevitable choice. Shield method is used in Shenzhen Metro and Nanjing Metro under construction. Guangzhou Metro Line 2, Shanghai Metro Line 3 and Beijing Metro Line 5 are all constructed by shield method. There are about 40 shield machines for φ6m subway, and some railway tunnels will adopt tbm. In the next 10 year, the demand for φ8.6m tbm will be about 6. A considerable number of hydropower tunnels will use tbm, and the demand for φ4m tbm is about 20. For pipeline construction in other cities, the demand for shield machines with φ 1.5 ~ 5m is about 100. Therefore, it is our goal and main task to replace import shielding in China. Based on the calculation of $5 million for each φ6m subway shield, if all 40 shields are imported, it will need $200 million in foreign exchange. The cost of each tbm with a diameter of φ8.5m in the railway tunnel is 30 million US dollars, and the import cost is about 65.438+0.8 billion US dollars. The cost of each tbm with a diameter of 4.5m in the hydropower tunnel is 654.38+0 billion USD, and 20 sets are about 2.