To understand the effects of anti-slip techniques between main cable and saddle of a three-tower suspension bridge with a rigid middle tower,five structural schemes are proposed,which are adding a central buckle,changing the rise-span-ratio,installing a buckling cable between tower and main cable,setting a steel structure on the top of tower and fabricating an assistant cable near the saddle.The calculated results by finite element method and analytical method show that the central buckling scheme and buckling cable scheme have little anti-slip effect,but the other three schemes are very effective.Based on these some design recommendations are given.