Abstract: Thickening mechanism and curing behavior of a novel phenolic SMC were discussed. The results show that the influence of water in phenolic resin, thickening agent, filler and silane coupling agent on the initial stage viscosity of phenolic resin paste is very obvious. It is found that use of calcium hydroxide as a thickening agent causes rapid hardening of phenolic SMC. Use of magnesium oxide alone as a thickening agent results in a slow hardening rate. Similarly, when talc alone is used as the filler, the viscosity of the phenolic resin paste increases rapidly ; when clay alone is used as the filler, the viscosity of the mixture increases slowly. But excellent viscosity control is achieved when a mixture of calcium hydroxide magnesium oxide, talc and clay is used. It has been discovered that the silane coupling agent cat alyzes the hardening and curing of phenolic SMC, which is proved by DSC data and gel time data. These research results provide the theoretical basis for producing a good quality of phenolic SMC.