The ultra-long pipe curtain (shed) often cannot be jacked or difficult to jack due to the influence of various factors, which directly affects the support effect. In order to establish a more effective risk assessment system for the jacking construction of long pipe curtain (shed), taking the Yaqutan Tunnel of Xicheng Railway as an example, based on the three elements of man-equipment-environment, the assessment system was constructed by considering four main aspects: personnel disturbance factor (I₁), material quality factor (I₂), mechanical equipment factor (I₃) and engineering geological environment factor (I₄). The risk assessment samples of the construction of ultra-long pipe curtain (shed) were collected, and the evaluation index parameter matrix was constructed. The subjective and objective weights of the index were determined by the Delphi method and the entropy weight method, and the combined weighting was calculated according to the principle of multiplication. Based on the Gaussian normal cloud model, the membership degree of the evaluation index is calculated, and the classic domain and node domain of the index are mined, and the comprehensive certainty of the evaluation system is constructed. The results show that the risk level of the 100-meter-level pipe curtain jacking scheme of the Yaqutan Tunnel belongs to the V. level, which belongs to the state of "extremely difficult jacking", while the risk level of the 40m-long pipe shed jacking scheme belongs to the level II., which belongs to the state of "easy jacking". The risk assessment results of the ultra-long pipe curtain (shed) jacking construction obtained by the "Gaussian normal cloud-combination weighting method" are consistent with the actual jacking situation, which verifies the feasibility of the comprehensive assessment system of ultra-long pipe curtain (shed) jacking construction based on Gaussian normal cloud theory, It can provide a reference for rock crushing and ultra-long pipe curtain (shed) in the early construction process.