This study was carried out to research the change of mineral phases and the characteristics (apparent specific gravity, water absorption, firing shrinkage and thermal expansion etc) of the sintered bodies composed of larnite, wollastonite and anorthite etc. in $CaO-Al_2O_3-SiO_2$ system. Test bodies were composed of the same theoretical composition as it of anorthite and fired up to $1450^{circ}C$. Investigated the change and micro-structure of the mineral phases by XRD and SEM, the characteristics of the sintered bodies by DTA/TGA and etc. The results were as follows. 1. The sintering temperature had a higher about $60^{circ}C$ than that of $CaO-SiO_2$ system because of coexisting $Al_2O_3$. 2. The formation and transition temperature of $eta$-wol lastonite and $alpha$-wollastonite were similar to the results of $CaO-SiO_2$ system. 3. The formed larnite and wollastonite were decomposed and melted at about $1260^{circ}C$. 4. Anorthite began to be synthesized at $1140^{circ}C$, its quantity was repidly increased according to the temperature rising.