Through the detailed risk evaluation on underground diameter project from Beijing railway station to Beijing railway west station, the conditions of all the risk sources along were analyzed adequately. At last, effective control measures of risk prevention and reduction were proposed based on the evaluations results. The settlement of all the measuring points of metro line 2 was lower than 2 mm. Due to the tunnel excavation the settlement of Tianningsi Bridge was lower than 3 mm. The construction impact on surrounding building was very small.