A new type of cooling device used in server was designed.Taking a server CPU as a research object, a mathematical model for thermal analysis was established and the temperature and velocity fields distributions were simulated.The simulated heat dissipation effects of air cooling and liquid cooling were compared to analyze the feasibility of the plan of forced convection liquid cooling.The effectiveness of simulation was proved by experiments.The results show that as the CPU is cooled by forced convection liquid cooling, the temperature distribution is more uniform and the temperature of the CPU is more stable in the condition of high power consumption(120 W).The device proposed can be applied in the cooling of a single server chassis, and can be extended further in the cooling of a small server workstation.The energy consumption analysis of the small server workstation shows that, comparing with the air-cooled heat emission, the energy consumption of air-conditioned computer room can be reduced by about 40%.