According to the existing practical engineering data, the settlement curve of shield tunnel with small curvature radius is obviously different from that of straight tunnel, so using Peck formula to forecast the surface settlement is not applicable. This paper describes results from a series of the laboratory test based on similarity theory carried out in sandy soil. According to the test results, the characteristics of surface settlement caused by small radius tunnel excavation are summarized, and the effects of turning radius and buried depth on the surface settlement are demonstrated. Based on Gaussian formula, a method to forecast the surface settlement caused by construction of shield tunnel with small curvature radius is developed.