In addition to the magnetic confinement fusion plasma, Thomson scattering (TS) has been applied to measure electron density and temperature of low-temperature plasmas. Based on Linear Magnetized Plasma (LMP) device, a set of incoherent Thomson scattering diagnostic system is designed to diagnose the plasma with ne=1018~1019m-3 and Te=2~5eV. Due to low plasma temperature and density, this diagnostic system needs high spectral resolution and collection efficiency to meet the requirements of electron velocity distribution function (EVDF) measurements. Through the bench test, the spectral resolution is confirmed to reach 0.01 nm, and theoretical collection efficiency is high enough to obtain Thomson scattering spectrum by 1000 accumulations.