The local bubble diameter profiles of the gas-liquid two-phase self-aspirated reversed flow jet loop reactor were studied experimentally by using internal camera CCD bubble measuring technology. The experimental results show that the local Sauter bubble diameter profile decreases with increasing liquid jet flowrates and nozzle diameter in both the jet region and the tubular flow region inside the draft tube. Bubble diameter profiles follow inverse Gaussian Distribution in the jet effective region while inverse parabolic distribution in the tubular flow region inside the draft tube.