The invention relates to resin and particularly relates a preparation method of MQ silicon resin. The preparation method comprises the following steps: adding deionized water, alcohol, silicate ester and a capping agent into a reaction container, stirring to obtain an emulsion-like reaction system; keeping the temperature of the reaction system at 20-55 DEG C, charging hydrogen chloride gas for 5-15min while stirring, then raising the temperature to 60-80 DEG C and reacting for 2-4h; after the reaction is finished, enabling the reaction system to stand still for layering, taking the lower layer to obtain a prepolymerized resin layer; raising the temperature to 120-150 DEG C, and removing volatile components under a 300-2000Pa vacuum condition to obtain colorless transparent MQ silicon resin, wherein the charging mode of the hydrogen chloride gas is that the hydrogen chloride gas is charged above the liquid level of the reaction system so as to be absorbed and dissolved by the reaction system. The reaction process is mild and easy to control; the reaction rate is improved greatly; no gel or undissolved substance is generated and the prepared product is clear and transparent. The preparation method is simple and easy to carry out and is suitable for industrial production.