The hydraulic performance of the H2O-30% trialkyl phosphine oxide (TRPO)-kerosene system and the mass transfer properties of HNO3 and Nd3+ were studied in a single-stage miniature centrifugal contactor with 10 mm diameter. A cascade cold test for partitioning Nd3+ from the simulated high-level liquid waste (HLLW) using the TRPO process was conducted on the miniature contactors. Based on results from the cold tests, a hot test for partitioning Am3+ from the genuine HLLW using the TRPO process was conducted on miniature contactors. The results showed that approximately 200 mL waste feed will allow the partitioning process with 24-stage miniature contactors; of 10 mm diameter to reach steady state. The test results also showed that the miniature centrifugal contactors have good hydraulic performance and high stage efficiency. The cascade cold and hot test results agreed well with calculations from extraction models.