The invention provides an organosilicon composition with low viscosity and a preparation method. The preparation method comprises the following steps: reacting organopolysiloxane and a coupling agent by a base catalyst, adding silica, regulating the crosslinking degree of organopolysiloxane and the coupling agent; then adding silicone resin to continuously react; adding silica and polyether modified polysiloxane, reacting and cooling to the room temperature. The obtained organosilicon composition has low viscosity, easy emulsification, excellent foam removing speed and foam inhibiting performance in an anion, nonionic foaming system.