A optimum design method of a new type of piezorsonance quartz temperature sensors using thickness shear c-mode is discussed. The crystal sensors consist of -cut crystal plates with plano-comex of the major surfaces which they are designed at 5MHz of frequency. Experimental data show that they are the temperaure sensors with ultra-high sensitivity and linearity. Measurement of 0.0005℃ temperature resolution and 0.07℃ linear frequency-temperature respones has been made.