Abstract: Family thought plays a very important part in Marx and Engels theoretical system. To them， a family is the sum total of multiple social relations. From the narrow sense， the family is the relationship between husband and wife and between parents and children; from the broad sense， the family is a part of nature and a microcosm of society. It has experienced the periods of group marriage family and even marriage family. Productivity is the decisive force in developing family forms and real monogamy can be realized only by reaching highly developed productivity and eliminating private ownership. Harmony is one of the essential attributes of the family， love is the foundation of the harmony between husband and wife， and the education children receive from their parents is the key to harmonious intergenerational relations. In other words， family and society together with family and nature are the unity of harmony.

Key words: Marx, Engels, family thought, family harmony