Objective: To establish a method for determining total diterpenoids in Platycladi Semen

investigate relationship of contents of fatty oil and total diterpenoids in Platycladi Semen

analyze influence of processing methods on quality of Platycladi Semen. Method: Vanillin-perchloric acid colorimetry was employed to determine the content of total diterpenoids

the content of fatty oil was determined by petroleum benzin.Platycladi Semen was processed by steaming

frying and frosting. Result: Total diterpenoids showed a good linear relationship in 0.011 7-0.058 3 g·L-1

RSD of recovery rate was 0.7%.Relationship between fatty oil and total diterpenoids was 87%.With steaming and frying method

contents of fatty oil and total diterpenoids significantly increased

but they decreased obviously by frosting method. Conclusion: Relationship between fatty oil and total diterpenoids in Platycladi Semen is a strong correlation.The content of grease composition increases with steaming and frying method

but they decrease by frosting method

and this method can reduce the side effect of Platycladi Semen.