Guide mechanism in boom of fluid conveying device and fire fighting truck

The utility model discloses a guide mechanism in a boom of a fluid conveying device and a fire fighting truck, a first pipe body and a second pipe body are mutually nested in a sliding manner, and the wall of the second pipe body relative to the first pipe body is provided with threads; a guide groove is formed in the wall, opposite to the first pipe body, of the second pipe body, and a guide block is fixedly arranged on the wall, opposite to the second pipe body, of the first pipe body; the guide block is arranged in the guide groove; the driving mechanism is arranged on the first pipe body, the driving mechanism is in transmission connection with the threads on the second pipe body, and the driving mechanism is used for driving the second pipe body to stretch out and draw back on the first pipe body. The guide block and the guide groove can prevent the first pipe body or the second pipe body from moving in the circumferential direction when the second pipe body stretches out and draws back; meanwhile, the f