The invention relates to a dimethyl dichlorosilane hydrolysate cracking process and plant. A hydrolysate storage tank is connected with a hydrolysate preheater through a hydrolysate conveying pump; the hydrolysate preheater is connected with a Venturi mixer; a catalyst storage tank is connected with the Venturi mixer through a catalyst conveying pump; the Venturi mixer is connected with a crackingreaction kettle; the cracking reaction kettle is connected with a cracking tower; the cracking tower is connected with a cracking tower condenser. The process comprises the following steps: injectinga proper amount of solvent oil into a horizontal cracking reaction kettle, preheating a part of dimethyl dichlorosilane hydrolysate, uniformly mixing with a catalyst, feeding into the cracking reaction kettle, and directly feeding the rest part of unpreheated dimethyl dichlorosilane hydrolysate into the cracking tower to control the temperature of the cracking tower under coactions of a crackingreflux. The cracking cycle of the dimethyl dichlorosilane hydrolysate can be prolonged to 35 days, the energy consumption can be reduced by about 25%, the unit consumption of the catalyst can be reduced to 0.2% or less, and a cracking annulus yield can be increased to 99.5%.