The pyroelectric material lithium niobate（LN）wafer can be used as sensitive layer material of pyroelectric detector.The dielectric constant and dielectric loss are two important parameters which determine properties of pyroelectric materials.When testing the parameters

in order to solve the problems of large quantities of datas

high precision requirements of measurement

longer testing time

a kind of automatic acquisition

automatic recording and processing system is presented

and curve of the dielectric constant and dielectric loss of LN wafer change with temperature before and after thinning is tested.Through data analysis

the relative dielectric constant of LN wafer tends to increase as the temperature increases

changes of the relative dielectric constant before and after thinning is not large

it is slightly reduced after thinning;dielectric loss of LN wafer tends to increase with the increase of temperature

it increases slowly below 160 ℃

but it increases rapidly above 160 ℃.Situation of dielectric constant and dielectric loss of LN wafer change with temperature accord with Debye model of dipole relaxation in low temperatures.