We present preliminary results of a study of the ultraluminous X-ray source UGC 6456 ULX .
The object is highly variable in both the X-ray ( more 100 times , 0.3-10 keV ) and optical ( more 2 times , V band ) ranges .
The peak X-ray luminosity of UGC 6456 ULX exceeds 10 ^ { 40 } erg s ^ { -1 } , the absolute magnitude in the bright state exceeds M _ { V } = -7.6 , which makes it one of the brightest ULXs in the optical range .
We found a correlation between the optical and X-ray fluxes , which may indicate that the optical emission is produced by re-processing of the X-rays in outer parts of the optically-thick wind coming from the supercritical accretion disk .
Optical spectra of UGC6456 ULX show broad and variable hydrogen and helium emission lines , which also confirms the presence of the strong wind .