Abstract: For belt conveyor driven by multi-motor, the problem of multi-motor power balance must be paid attention to for preventing equipments from being destroyed by unbalanced loading on individual motor. The paper introducd structure and working principle of hydro-viscous driver and principle of its hydraulic servo control system, gave principle of a current control method which uses hydro-viscous driver to achieve multi-motor power balance of belt conveyor, namely, the control oil pressure of the hydro-viscous driver is changed to adjust load of each motor by changing current of every electro-hydraulic proportional valve used in the hydraulic servo control system of hydro-viscous driver, so as to change currents of motors and make all the motors can work with the same power or with power difference within allowed range. The practical applications showed that adjustment of power balance of belt conveyor by the current control method not only meets requirements of startup and power balance of the belt conveyor, but also is convenient to install and maintain and economic.