The control of Hg pressure is a major problem of LEP growth of HgCdTe. In this paper the lost of Hg and its affections and control in open tube sliding LEP system are analysed theoretically. A unique method of controlling Hg pressure, called pseudo-balance Hg pressure method is proposed. In this method, a circulatory system of Hg that is efficacious for control of Hg pressure is used. By experiments of growth conditions, the better way of LEP growth of HgCdTe was found. The HgCdTe epitaxial layers have been grown with mirror-like surface morphology, x=0.2110.002 and x=0.280.001, mobility of 1.81103cm2/Vs for p-type and 3.36105cm2/Vs for n-type (not annealed), carrier concentration of 1.041016/cm-3 for p-type and 1.091015cm-3 for n-type (not annealed) at 77K.