  Single crystals of K0.58Fe1.56Se2 were successfully synthesized by a new
single step process with the onset superconducting transition temperatures 31.9
K. The x-ray diffraction patterns suggest that they have high crystalline
quality and c-axis orientation. A possible modulation structure of Fe-vacancy
along c axis was observed. The upper critical field has been determined with
the magnetic field along ab-plane and c-axis, yielding an anisotropy of about
3.3. It has also been shown that the critical current density of the
K0.58Fe1.56Se2 is about 1.7x10^4 A/cm^2 at 5 K.
