3D ICs has the potential to reduce the interconnect delay, but thermal problem becomes one of the most serious challenges. In this paper, we proposed an efficient thermal aware 3D placement algorithm based on an efficient 3D DCT placement which unified cell distribution and wire length into one quadratic function through cosine transformation (DCT) and utilized iterative quadratic placement idea to get the solution. To utilize the advantage of DCT idea, thermal dissipation, cell distribution and wire length are integrated together elegantly in our proposed thermal aware placement algorithm. Thermal distribution was considered enough during placement process even when a cell was moved. Two fast methods to reflect thermal charge were proposed for thermal distribution computation. The experimental results shows our thermal aware 3D placement algorithm is efficient with about 3% reduction in average temperature and 15% in max temperature but a little perturbation on wirelength.