The composition uniformity of a HgCdTe bulk material used as liquid-phase epitaxial solution was studied. By optimizing the compound temperature, compound time, furnace swing frequency and quench process, the longitudinal composition uniformity of the HgCdTe bulk material was improved greatly. 28 epitaxial film samples were grown by using the HgCdTe bulk material compounded after the growth process was modified. They had a average composition uniformity of 0.95\% which met the fabrication requirement of the second generation infrared focal plane arrays.