Since the middle of 2005, a high seismic activity has been observed in Emeelt that is located at a distance about 10-40 km in the west from Ulaanbaatar city in Mongolia. First, we performed relocations of earthquakes around Ulaanbaatar city. We used a one dimensional P wave velocity model obtained by a recent study of seismic tomography as a velocity model for relocation. Then we determined 33 focal mechanism solutions using P wave polarity data and SH/P amplitude ratios of earthquakes with magnitudes ≥ 2.5 around Ulaanbaatar city. We obtained the focal mechanisms for nine earthquakes in the Emeelt swarm area. Five of them have the strike slip focal mechanisms. Most of the compressional (P) axes are oriented to the NE-SW direction and the tensional (T) axes are oriented to the NW-SE direction in the Emeelt swam area. The lateral extent of the swarm activity is in the tension direction inferred from the focal mechanisms. The P and T axes of focal mechanisms of the other 24 earthquakes obtained around Ulaanbaatar city shows a larger spatial variation.