The invention belongs to the technical field of excavator intelligent control and testing and discloses an elevator rotary detecting device, an elevator control system and method, and an excavator comprising the excavator rotary detecting device or the excavator control system. The rotary detecting device comprises a transmission shaft, a gear, an encoder and a controller. The gear is engaged witha rotary support, and under the condition that an upper vehicle rotates around the rotary support, the gear automatically rotates so as to drive the transmission shaft to rotate. The encoder is connected with the transmission shaft and used for collecting the rotating angle of the transmission shaft. The controller is used for calculating the following one or more of the rotary angles, the rotaryspeeds, the rotary accelerated speeds and braking angles corresponding to the different rotary speeds of the excavator according to the rotating angle of the transmission shaft and the tooth number ratio of the rotary support to the gear. A worker can accurately measure the rotary performance of the excavator in real time, and rotary intelligent control of the excavator is achieved.