In Nanling Mountain area, a very important metallogenic province of China, the various granitic rocks with different ages are widely distributed. During the evolution of these granitoids which resulted from rejuvenation and anatexis of the old basement (1200-2000Ma), the main ways for REE differentiations were: (1) partial melting; (2) fractional crystalization; (3) thermogravitational diffusion; (4) differentiations of metamorphism and migmatism, and (5) hydrothermalism. Among them the (2) and (3) processes are the most important ones for HREE concentration in magma. Based on the data of tectonic setting, lead and strontium isotopic compositions and zircon population types, it is concluded that local physicochemical environment of magma is the key constraints to REE fractionations.