An on-line monitoring and troubleshooting assisting system of a ball mill includes a host computer touch screen, a slave computer industrial controller and an execution lay device element. The monitoring picture of the host computer touch screen can respectively display an initial picture, a main picture, a main motor start allowing condition picture, a pneumatic clutch close allowing condition picture, a slow drive allowing condition picture, a petrol filling station system picture, a high pressure oil flow trend diagram picture, a high pressure oil pressure trend picture, a ball mill main bearing temperature trend diagram picture, a pinion bearing temperature trend picture, a main motor temperature trend picture P11, a ball mill vibration trend diagram picture, a parameter setting picture, an alarm record picture and an alarm information fault processing assisting picture. The host computer touch screen is connected with the slave computer industrial controller through an MPI cable or Ethernet cable to communicate and read the data of the slave computer industrial controller, the slave computer industrial controller is connected with the execution lay device element to exchange data, and the on-line monitoring and troubleshooting assisting system of a ball mill has a good man-machine interaction interface and visual effect, and is easy to operate.