Abstract: In this paper, the voltage distributions and the probability distribution densities within the range of voltage fluctuations in a silver deposition system are investigated. The optimal degree of expansion of fluidized bed is obtained and some other important problems such as the influence of temperature on the silver deposition rate, the change of current efficiency with the concentration of Ag+ are also studied. The experimental results show that, under smooth fluidized state, all the particle voltage, electrolyte voltage and overvoltage follow the Gaussian probability distribution density within their fluctuation ranges, but when slugging or channeling appears such relationships no longer exist. The mean values of the voltage do not change in the x and z directions, but change in the y direction for the reactor used. Near the collector and the membrance the over-voltage is higher. The influence of temperature on the deposition rate of silver is rather small. The experimental results also show that the Ag+ in the electrolyte can be deposited rather completely, but when the electrolyte becomes very dilute the current efficiency decreases sharply.