The successful implementation of the state family policy exists in a steady dependence on the main principles established in the legislation, ensuring legalization and law obedience through the understanding by the population of the objectives of legal regulation. The article redefines and justifies the transformation of the principle of «family autonomy» under the influence of social processes and values, gives an author’s formulation. Proposals are put forward for the inclusion of a new principle - flexibility, consistency, effectiveness and differentiation of state policies to support families and popularization of family way of life.