The modulated frequency dependence on the pyroelectric properties of LiTaO$_3$ single crystal was investigated by the dynamic method. The pyroelectric coefficient of LiTaO$_3$ single crystal was 2.1${ imes}$$10^{-8}$/$ extrm{cm}^2$ㆍK. and figure of merits for the responsivity and the detectivity were 1.31${ imes}$$10^{-10}$Cㆍcm/J and 1.47${ imes}$$10^{-8}$Culcornercm/J. respectively. The voltage responsivity corresponded with the pyroelectric voltage exhibited the highest value as about 165V /W at 4Hz and then was in inverse proportion to the frequency over 20Hz. The noise equivalent power and the detectivity at 4Hz were 8.4${ imes}$$10^{-9}$ W/Hz$^{1}$2/ and 2.2${ imes}$$10^{7}$ cmㆍHz$^{1}$2//W, respectively. Therefore, we could found that LiTaO$_3$ single crystal shows a excellent pyroelectric properties in low frequency region for the human body detection.tection.