$MgTiO_3{cdot}CaTiO_3{cdot}SrTiO_3$ system ceramics (MCST) were synthesized to study the effect of Ca addition amount and Sr substitution on temperature coefficient of resonance sequency. Temperature coefficient of resonance frequency was slightly increased by small amount ($i.e.{sim}5%$) of Sr substitution. In case of 50% to 75% addition amount of $MgTiO_3$, decrease of quality factor was not observed with increasing dielectric constant.