Fluid-absent melting of crustal rocks as an important mechanism of genesis of granitoids has been known for twenty years. During recent ten years experimental melting and modeling associated with granitoids mainly were focused on melting reactions, melt fraction produced and favourable conditions in fluid-absent melting of crustal rocks. This paper summarizes the major results from fluid-absent melting experiment and modeling and those results constrain on the genesis of granitoids. It is suggested that study of genesis of granitoids in a special area must consider the melt fraction produced by fluid-absent melting of different rocks, if high-heat state can be retained by mass and energy transport in the regional lithosphere, and considered that simple applications of general criteria of I-and S-type granitoids to identifying the relations between genetic classifications and source rocks is not suitable.