Abstract: Surface settlement is an important basis for judging stability of tunnel surrounding rock, and also the key item in tunnel construction monitoring and measurement. The surface settlement law of shallow-buried tunnels under asymmetrical pressures is more complicated and more likely to induce safety accidents compared to the symmetrical loading tunnels, and so it is necessary to conduct in-depth study. Based on the maximum principal stress deflection theory, firstly a quantitative analysis on the asymmetrical loading degree of a tunnel was carried out, the concept and calculation method of tunnel unsymmetrical pressure coefficient were proposed; secondly an equivalent calculation model was established, and the surface settlement of a shallow-buried tunnel under asymmetrical pressure was regarded as superposition of asymmetrical loading terrain and pressure, a calculation method and procedures were given; finally the surface settlement law of shallow-buried tunnels under asymmetrical pressure was further analyzed by field measurement data, and the prediction results were verified. The results show the unsymmetrical pressure coefficient is related to surface bias angle, tunnel overburden and lateral pressure coefficient; surface settlement curve will be twisted under effect of asymmetrical pressure, the maximum settlement area and influence range will be shifted towards the deep-buried side; if asymmetrical pressure is large, it′s easy to cause cracking of surface at deep buried side and staggering at the shallow-buried side.