Large-size cultivated diamond synthesis block

The invention relates to the technical field of diamond synthesis, and discloses a large-size cultivated diamond synthesis block which comprises a pyrophyllite synthesis block, an outer liner tube is arranged in the pyrophyllite synthesis block, a nickel strap is wound outside the outer liner tube, and pyrophyllite rings, dolomite rings, temperature adjusting rings, iron sheets and molybdenum rings are symmetrically arranged on the upper side and the lower side of the outer liner tube. The interior of the pyrophyllite ring and the interior of the dolomite ring are communicated and form a containing cavity, a steel ring, a first graphite sheet and a molybdenum sheet are arranged in the containing cavity, an iron column is arranged in the temperature adjusting ring, a graphite pipe is arranged in the outer lining pipe, and an upper BON sheet, an insulating pipe and a lower BON sheet are arranged in the graphite pipe. A nickel sheet I, a samarium oxide sheet, a graphite sheet II, a carbon ring, a catalyst sheet