The invention discloses a fine machining device and technology of the surface of die steel, and relates to the field of die production and manufacturing. The fine machining device comprises a workingtable, the working table is vertically provided a support seat, and the support seat is vertically and slidably connected with a sliding seat; the lower end surface of the sliding seat is rotatably connected with a rotating seat, and a pneumatic clamping jaw is arranged on the lower end surface of the rotating seat; a polishing pad is arranged on the upper end surface of the working table, a liquid supply mechanism is arranged on the side wall of the support seat, the liquid supply mechanism is provided with a liquid discharging pipe, the liquid discharging pipe is provided with a valve, and the pipe opening of the liquid discharging pipe aligns with the surface of the polishing pad. The fine machining device and technology have the advantages and effects that through matching of polishingliquid and the polishing pad, ultra-precision fine machining of the die steel is achieved in the alternating process of the chemical reaction and mechanical action, and thus the fine machining accuracy of the die steel is improved; and meanwhile the steps are set to be simple, the fine machining technology with high automation is achieved, the accurate machining of the die steel is achieved, andthe fine machining accuracy of the die steel is improved.