Mercury sulfide was synthesized by a controllable solvothermal method. X-ray diffraction, transmission electron microscopy and X-ray photoelectronic spectrum were used to characterize as-prepared mercury sulfides. Both hexagonal and cubic phase of mercury sulfide can be synthesized via this method. The phase transition of the two phases and the mechanism of morphology controlling in different solvents were studied. The results show that in the solvothermal reaction higher temperature is favorable for the phase transition from metacinnabar to cinnabar and polyamides play an important role in the forming of nanorods,