A method for purification and conditioning of crude syngas based on properties of molten salts, includes removing particles at a high-temperature by enabling the high-temperature crude syngas produced by a gasification device to firstly pass through a high-temperature particle removal device to remove solid particles in the gas; removing hydrocarbons in the presence of oxygen by introducing an oxidant into the crude syngas after treatment, selectively removing the hydrocarbons in the crude syngas and simultaneously utilizing high temperature produced by oxidation of the hydrocarbons to crack tar; and removing gas pollutants and conditioning by introducing the obtained crude syngas into molten salts medium, removing pollutants containing sulfur and chlorine in the crude syngas, and simultaneously adjusting the H2/CO ratio of the syngas to obtain purified syngas.