The invention discloses heat conduction flame retardant liquid silica gel, which comprises components with the following parts by weight: 10 to 40 parts of vinyl end organopolysiloxane with 500 to 5000 mPa.s polymeric viscosity in 25 DEG C, 10 to 40 parts of vinyl end organopolysiloxane with 10000 to 50000 mPa.s in 25 DEG C, and 1 to 5 parts of hydrogen-containing polymethylsiloxane, 2 to 8 parts of alkyl disilazane, 20 to 50 parts of surface hydrophobicity Al2O3 powder with average particle diameter of 5 to 20 microns, 10 to 50 parts of Al(OH)3 powder with average particle diameter of 5 to 20 microns, 0.3 to 2 parts of addition solidification catalyst, 0.01 to 0.06 part of alkynol depressant and 0.5 to 2 parts of distilled water, wherein, R is methyl, ethyl, propyl or butyl. The invention is prepared by the way of addition type heat vulcanization, toxic substance or irritant gas is not produced in the production process, the vulcanization rate is quick, and the energy saving, the consumption decreasing and the environmental protection requirements are conformed. The storage stability of the product is good, the viscosity is moderate, the operability is good, the product integrates the heat conduction, insulation and flame retardant performances into a whole, and the performance-price ratio is high.