The energy consumption of the air-conditioning system in the Internet Data Center (IDC) occupies about 40% of the total energy consumption. The thermosyphon heat exchanger using ambient energy is applied in the IDC to reduce energy consumption. By taking one IDC in Beijing as reference, the testing model is set up to experimentally analyze the heat dissipation characteristics and the energy consumption of thermosyphon heat exchanger and air-conditioning system respectively. The result indicates that the heat dissipation capacity of the building envelope takes about 19.5% of the total IDC heat load in Beijing winter conditions. The average energy consumption of the air conditioner is 3.5 kW h ~ 4 kW h per day. And the energy consumption of the thermosyphon heat exchanger takes only 41% of the air conditioner. The annual energy consumption reduces by nearly 40%. Besides, the effect of the outdoor temperature on the air conditioner energy consumption is remarkable compared with the indoor set temperature. And the air conditioner energy consumption increases by 5% ~ 6% on average when the outdoor temperature raises by 1℃.