The focus attention in this research is on the material and thickness of Low-Temperature Differential Stirling engine regenerator. The displacer regenerator was chosen. The activated carbon filter and formcores were chosen as the regenerator material. The dimension of the engine is 120 mm × 120 mm × 165 mm；the weight of the engine is 380 grams；the dimension of the displacer is 94 mm. Electron heater was adopted for heating；natural convection was adopted for cooling；the range of input power was 5 W, 10 W and 15 W；environment temperature was 28±1℃；operation temperature was 52℃ to 108℃. The range of formcore thickness is 1 mm to 7 mm. Engine speed was measured with different regenerator material and thickness. The research indicates that engine speed with formcore regenerator is faster than activated carbon filter regenerator. The increase of engine speed is caused by the increase of the thickness. The best thickness is 6 mm.