Surface modified Zn-Mg-Al hydrotalcite was prepared by coprecipitation. And its performance, as a PVC thermal stabilizer, was evaluated by torque rheometer and static thermal aging method. Effect of Surface modifier on the thermal stability of Zn-Mg-Al hydrotalcite was specially investigated in this paper. The results showed that Zn-Mg-Al hydrotalcite, modified by polyethylene glycol, performed the best property for the inhabitation of PVC initial coloration and long-term thermal stability. In addition, effect of Zn/Mg molar ratio on the thermal stability of Zn-Mg-Al hydrotalcite was also investigated. Polyethylene glycol modified Zn-Mg-Al hydrotalcite performed relatively better thermal stability when Zn/Mg is 1:3 or 1: 7. Compared with traditional Mg-Al hydrotalcite, modified Zn-Mg-Al hydrotalcite showed better property for the inhabitation of PVC initial coloration.