OBJECTIVE： To optimize the processing technology of rehmanniae radix praeparata. METHODS： Using transfer rates of catalpol， rehmaionoside D， acteoside， isoacteoside， polysaccharide as indexes for comprehensive score， heating temperature （pressure）， heating time and heating times as investigating factors， L9（34） orthogonal test was used to optimize the processing technology of rehmanniae radix praeparata， and verification test was conducted. RESULTS： The optimal processing technology of rehmanniae radix praeparata was as follow as heating temperature of 125 ℃， pressure of 150 kPa for twice， 2 h every time. The comprehensive scores of 3 batches of samples were 0.698 5， 0.675 5， 0.701 6 in the verification test， respectively， RSDs were less than 5％ （n＝3）. CONCLUSIONS： Optimized processing technology is simple， stable， feasible， and can provide reference for industrial production of rehmanniae radix praeparata.