Xincheng tunnel on Hangzhou Jiefang Road extending highway is a twintube tunnel that is supershallowburied, largespanned and closespaced, as well as running within poor geological conditions and underneath existing ShanghaiHangzhou railway, therefore the construction of the tunnel contains extremely advanced technology. The article introduces the comprehensive technology and the corresponding assistant measures adopted during the construction of the tunnel underneath the railway. Furthermore, by means of feedback of the monitoring results, the article analyses and explains the successful application of shallowburied undermining method and its comprehensive assistant technology in the tunnel construction, which  has important practical significance.