In this paper,the influences of different protective layer materials(marble,cement mortar,epoxy resin) on the performance of the resistance and capacitance during the fabrication process of the smart aggregate has been studied,the performances of the smart monitoring system composed of smart aggregates with different protective layer materials have been compared,and two indexes of signal amplitude and linear sensitivity are investigated. The test results show that the marble protective layer and epoxy resin protective layer has no effect on the resistance value of smart aggregate, while the protective layer of cement mortar has a significant influence on the resistance value of the PZT sheet,the resistance value of the cement mortar is small when the cement mortar is wet,and the resistance value is large when the mortar is dry.The protective layer material has a great influence on the capacitance value of smart aggregate,in which the cement mortar protective layer has the greatest influence on the capacitance, the amount of variation is between 18%~27%,followed by marble, between 18%~22%,the epoxy resin protective layer has the least influence on the capacitance,between 17%~20%. In the smart monitoring system composed of smart aggregate which are made of different protective layer materials, the signal amplitude and sensitivity of the smart aggregate with marble protective layer are the highest,the second is cement mortar,and the last is epoxy resin. It is concluded that the marble is the most suitable material for the protective layer of smart aggregate.