The invention discloses a reaction apparatus used for catalytic gasification of petroleum residues by fuse salt and a method using the same, belonging to the technical field of energy utilization. The reaction apparatus comprises a gasification reaction device and a gas separating and purifying device, wherein the gasification reaction device comprises a shell, the fuse melt is arranged in the inner cavity of the shell, the gas separating and purifying device is connected with the gasification reaction device, and an adsorbent is arranged in the gas separating and purifying device. In usage of the reaction apparatus, the petroleum residues undergo a reaction in the gasification reaction device under the catalysis of the fuse salt so as to obtain a crude synthetic gas product; then the crude synthetic gas product enters the gas separating and purifying device; and impurity particles and gaseous metal ions in the crude synthetic gas product are separated via the adsorbent so as to obtain pure synthetic gas. The reaction apparatus used for catalytic gasification of petroleum residues by the fuse salt and the method using the same realize continuous high-efficiency gasification of the petroleum residues at a low gasification temperature and effectively recover precious metal components in the petroleum residues.