(57) The present invention relates to a process for continuously producing an ultra-high molecular weight polyethylene by the ethylene slurry polymerization, wherein raw materials containing ethylene and optionally at least one comonomer are subjected to a continuous slurry polymerization in a hydrogen free atmosphere in the ethylene slurry polymerization condition by using 2-6 ethylene slurry polymerization reaction tanks connected in series, and the deviations of the polymerization temperatures, the polymerization pressures, and the gas phase compositions between the tanks each other are controlled to certain ranges. The ultra-high molecular weight polyethylene having the viscosity-average molecular weight of 150-800 ×10⁴ g/mol can be continously produced. This process has flexible polymerization manner, large room for adjusting and controlling, and stable polymer performance. Moreover, the obtained ultra-high molecular weight polyethylene has low metal content, low ash content, and excellent mechanical properties.