Polyvinyl acetate (PVAc) emulsion is a common conservation material used for conservation of painted cultural relics. In this study, the thermal stability, structure, morphology and particle size of PVAc emulsion were characterized and analyzed using thermogravimetric-differential thermal (TG-DTG) analyzer, Fourier transform infrared (FT-IR) spectrometer, X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and laser particle size analyzer. The relationship between the concentration of PVAc emulsion and its viscosity, surface tension, pH value and conductivity were investigated using a viscometer, surface tension meter, pH meter and conductivity meter, respectively. The stability of the PVAc emulsion was examined by freezing and thawing test, room temperature-high temperature placement, and centrifugal separation. In addition, to further verify its properties, the PVAc emulsion was used for the restoration of flaking and disrupted murals. The results show that 1) the particle size of the PVAc emulsion was bimodal, the average particle size of small particles was 380 nm and the average particle size of large particles was 5.85 μm; 2) the final mass residue of the film was 1.54%, the exothermic peak appeared at 335 ℃, and the emulsion was of amorphous structure; 3) with the increase of the PVAc emulsion concentration, the surface tension decreased and the relative viscosity increased； 4) PVAc emulsion is stratified by freeze-thaw, centrifugal separation and room temperature-high temperature placement. After repairing the flaking and disrupting murals, the samples are cycled for 20 times and aged for 12 times, respectively. It was found that the repairing murals were again flaking and disrupting. All results suggested that the PVAc emulsion used in this work has poor stability and anti-aging performance. Therefore, during the restoration of painted cultural relics, the influence of PVAc type, PVAc concentration, and environmental factors on its performance should be carefully selected to achieve the best effect in use.