The invention relates to a detection method for the operation state of rotary furnaces, a system thereof and a furnace adjusting method. The detection method comprises: correlating the rotation direction of a rotary furnace and the detected working current curve of a furnace drive motor, the rotation direction of the rotary furnace, and detected the mechanical parameter curves about force on eachsupport wheel and furnace transmission small gear base, to realize online detection for the abnormal change of the operation state of the rotary furnace; according the average value of the working current of the furnace drive motor in each rotary period of the furnace, the difference between the maximum and minimum values of the working current, the decrease of the mechanical parameters about force of each support wheel and furnace transmission small gear base, referring to the measurement results of the rotation central line of the rotary furnace and the geometric position of each support wheel, to confirm the adjustment direction and data of each support wheel, according to the average value of the working current of the furnace drive motor, the decreases of the difference between the maximum and the minimum values, and the decreases of the mechanical parameters about the force on the support wheels, judging the correctness of the direction adjustment of each support wheel, decidingthe accurate adjustment value of each support wheel. The device is simple, and has simple operation, reliability, long service life, high performance price ratio and wide application.