The Jiaochang arc belt in Songpan—Garze fold belt is composed with three partitions: arc roof, arc kern, arc limbs，which are different from each others according to the structural feature in field and microstructural feature. The deformational strength becomes shallower from the south to the north, which is mainly ductile strain in south and brittle deformation in north, as well as metamorphic fluid becomes stronger active in Himalayan Epoch according to ESR. Arc kern separates the arc roof from arc limbs, which imbricatly thrusts from south to north, while the later has different feature in activity of metamorphic fluid and deformational strength between western limb and eastern limb. In a word, the Jiaochang arc belt is totally characteristic of multiphase compressional—tensional movements in north—south trending, overprinted compressional metamorphose in （NW—NNW）—（SE—SSE） trending on orogenic epoch. The macro and micro structural feature in Jiaochang arc belt is different from the “strikeslip” mechanism of arc belt, compared with the tectonic setting, it is concluded that the mechanism of the Jiaochang arc belt is owe to combined effect of the Qinling orogen belt and Upper Yangtze block.