In this paper, the relationship between the conveying pressure drop and the gas velocity were firstly characterized based on pressure signal analysis. The critical gas velocity was obtained to classify the transfer bottle into stationary station and motion state, and pressure fluctuation characteristics in each state were determined. Further, derived from the traditional additional pressure drop method, the model for pressure drop prediction was developed. The gas pressure drop was further divided into four terms, including those in the conveying pipe, through the sudden contraction from the pipe to the head of the transfer bottle, through the sudden expansion from the end of the transfer bottle to the pipe, and through the gap between the bottle and the pipe. The solid-phase friction pressure drop was determined based on correctly estimation of the dynamic friction coefficient.The model can satisfactorily predict the pressure drop, giving errors mostly smaller than ±10%.