The resin/asphaltene (R/A) mass ratio will affect the natural pour point depressant (PPD) effect of asphaltene and the synergistic effect between asphaltene and polymer PPDs, but studies of these two aspects are scarce. To improve people's theoretical cognition on the waxy crude oil rheology and guide the application of polymer PPD more reasonably, in this work, the effect of the R/A mass ratio (0.5:1−4:1, the asphaltene concentration is fixed at 0.5 wt %) on the rheology of model waxy oils undoped/doped with 100 ppm EVA was investigated. The results showed that adding asphaltene alone and adding EVA alone can improve the rheology of waxy oil to some extent, but adding resin alone aggravates the rheology of waxy oil. The aggravating effect increases with increasing the resin concentration. Adding both asphaltene and resin in undoped waxy oil inhibits the natural PPD effect of asphaltene, and the waxy oil rheology continuously is aggravated with increasing R/A mass ratio due to the stronger nucleation effect and the formation of more small wax crystals. For the waxy oil doped with EVA, adding resin alone greatly inhibits the performance of EVA; adding asphaltene alone aggravates the waxy oil rheology, indicating a synergistic aggravating effect between asphaltene and EVA; when both resin and asphaltene are added, however, the rheology of the waxy oil improves significantly, indicating a synergistic improving effect between asphaltene and EVA. The synergistic improving effect first enhances and then slightly weakens with increasing R/A mass ratio. The best synergistic improving effect is found at R/A = 1:1. The dispersion state of asphaltene dramatically influences the synergistic effect between asphaltene and EVA: without resin, the poor dispersion state of asphaltene results in a synergistic aggravating effect; with resin, the asphaltene is well dispersed and then a synergistic improving effect is found.