Infrared spectroscopy was used to determine 1,648-1,589 cm(-1) characteristic absorption peak area so as to study the conversation of acrylic C=C double bonds after UV curing. The effects of phototinitiators, active diluents and UV curing resins on the conversion of C=C double bonds were also investigated. The results showed that 40%-85% of C=C double bonds were conversed during dark reaction after 45 s UV curing. Dark reaction will be changed gently after 1.75 h, but 95% conversion of C=C double bonds needed more than 24 h. The rates of polymerization and conversation were affected by photoinitiators, the concentration of photoinitiator, oxygen inhibition, and C=C functional groups of active diluents. The rate of polymerization was affected by the C=C functional groups and types of UV curing resins, but conversation was not.