Abstract: An improvement by using double thermostat for the device of reducing temperature effect on the CG-2 gravimeter has been described. Further tests were made to remove the slow yearly variation of amplitude 500 microgals of gravity by raising the precision of teme-prature control from 24℃ 0.15 in the case of single layer SCR thermostat to 25℃0.02, under the same condition of yearly room temperature change of 10℃. The paper gives also the constructional details of the device.