Plaster plays a vital role in the ancient architecture. Tung oil was stewed and used as an additive Tu ziand Zhang dan before the plaster used. FTIR, rheometry, power curve of oxygen and a means of chemoluminescence were used to analysis the role of Tu zi and Zhang dan. The results show that polymerization transition occurred during the tung oil stewing and Zhang dan is the catalyst in this process.Tu zi has the effect of inhibiting tung oil polymerization.