The invention discloses an inner cleaning device for a petroleum pipeline. The left side of an inner cavity of a support drum is provided with a first motor. The first motor is fixedly connected with the bottom of the support drum. The left end of the first motor is provided with a rotary shaft inserted into a hole. The left end of the rotary shaft is fixedly connected to a cleaning brush. The middle part of the support drum is provided with a storage battery. The lower end surface of a telescopic rod is connected with the bottom of the inner cavity of a sleeve through a spring. The upper end of the telescopic rod is provided with a pulley. Support pulleys are symmetrically arranged on two sides below the outer wall at the left end of the support drum. The bottom at the right end of the support drum is provided with a baffle plate. The middle at the right end of the baffle plate is provided with a motor reversing touching device electrically connected to a second motor. The inner cleaning device for petroleum pipeline has the following beneficial effects: automatic cleaning operation is carried out within the pipeline; the cleaning brush can be in full contact with the inner wall of the petroleum pipeline so that cleaning is more thorough; the cleaning device is provided with the motor reversing touching device so that the inner cleaning device may automatically go back when encountering large obstacles.