Pressure recovery characteristics of diverging mixing tubes were investigated. The total pressure at the exit of the diverging mixing tubes decreased when the diverging angles increased. More than 50% of the total pressure loss was observed in our experimental results. The flow fields in the diverging mixing tubes were investigated in numerical simulations. It was found that energy distributions in the diverging mixing tube agreed with those in the constant-area tube with in 1 kJ. The transformation of the energy with the increase of the cross-sectional area was controlled in the diverging tubes. Based on this numerical result, a one-dimensional model to predict the total pressure loss was proposed. The analytical results obtained by the one-dimensional model were compared with the experimental and numerical results. Good agreements within 15% with the experimental results were obtained.