The application of construction and demolition (C&D) waste and used tires in geotechnical engineering contributes to the demand of the sustainable development. This study mainly compared the mechanical behavior of pure sand embankment (PSE), C&D material embankment (CDME), sand-tire shreds mixture embankment (STSME) through a scale model test. Effects of tire shreds content, the first layer geocell reinforcement burial depth, geocell reinforcement depth and compaction degree on the bearing capacity of embankments were investigated. Moreover, embankment load-settlement ratio, the reinforced bearing capacity ratio, the bearing capacity improvement factor (IF), the embankment surface deformation, and the vertical earth pressure distribution inside the embankment were discussed. Results indicate that both C&D material fillers and sand-tire shreds mixture can improve the bearing capacity and stability of embankment slopes. However, C&D material is better than sand-tire shreds mixture in the improvement. The optimum value of tire shreds content is 5%. The reinforcement effect of geocell decreases with the increase of reinforcement depth. With the increase of the buried depth of the first layer, it first increases and then decreases. With the increase of compaction degree increases. The minimum earth pressure appears near the slope. The bearing capacity of CDME is greater than STSME. The ultimate bearing capacity of CDME under the action of the geocell is twice that of the unreinforced embankment.