Maevatanana gold deposit is located in the central part of Madagascar. Because of thick sediments, very little paper is reported about the Maevatanana gold deposit in Madagascar. In the Maevatanana gold district, ZK3-5 drill hole shows gold mineralization underside the granite vein, and the timing of metallogenesis at 534±13 Ma, as determined by the 187Re–187Os isochron age on pyrite, this is virtually coeval with the emplacement of post-collisional granite between 537 and 522 Ma during the waning stages of the East African Orogen. Field observation and experiment data indicates that the Maevatanana gold deposit is closely associated with the post-collisional granites after the East African Orogen, which were derived from mantle. The mafic magmas underplate the lower crust, generating voluminous felsic magmas by partial melting of the lower crust. Meanwhile, felsic-mafic magma mixing during the tectono-thermal reactivation of the East African Orogen produced voluminous volatiles. The volatiles extracted gold in the felsic magmas. Therefore, magma mixing during the tectono-thermal reactivation of the East African Orogen, which was important for the formation of the Maevatanana gold deposit.