Aimed at the problem of multi-motor synchronization in multi-wire saw, Strategy based on model-free adaptive control (MFAC), which has some characteristics such as without accurate system model, without system identification and without complicated manual tuning, is produced. MFAC is based directly on pseudo-partial-derivatives (PPD) derived on-line from the input and output data of the system using a novel parameter estimation algorithm. It is suitable for multi-wire saw in such a complex system which is nonlinearity, strong interference and strong coupling. Overall design of multi-wire saw is analyzed. Control structure of multi-motor is given. Motion model of multi-motor synchronization is established. To speed of main motor for reference, supply spool motor and collect spool motor, which have similar dynamic characteristics with main motor, are adjusted adaptively to follow operation of main motor, and synchronization motion is ensured. The prototype experiments show that the method used is right and feasible.