Pagoda of Six Harmonies is a protected unit of cultural relics in China whose last maintenance dates back to the 1990s. Now Pagoda of Six Harmonies needs to do some preventive maintenance which required protecting the visitors' normal visit. This time a new type of suspension truss cantilever scaffold is used in the engineering. Numerical simulation and 1:1 model load test are employed to prove the serviceability of applying the suspension truss cantilever scaffold to maintain the Pagoda of Six Harmonies. The result of the numerical simulation and the model test is used to comparative study. Comparing the loading performance shows the stress of the members smaller than the structure's critical load intensity. In the meanwhile， the strain and deformation conform to the national standard. Therefore， the scaffold can be applied to the engineering successfully. This paper provides a reliable technical support for the preventive maintenance of the pagoda of Six Harmonies.