Objective: To explore the effects of different drying methods on the quality of Cinnamomum camphora leaves

in order to provide the theoretical reference for determining the industrial extraction process of C. camphora. Method: Fresh leaves were treated with four drying methods

such as natural drying

constant temperature blast drying

vacuum drying and vacuum freeze drying; the appearance and morphological characteristics of dried leaves

and microscopic structure of leaves powder were observed. The volatile oil was extracted and purified by ultrasonic assisted steam distillation. The ingredients of D-borneol

camphor and isoborneol were determined by gas chromatography-mass spectrometry (GC-MS). Result: In the naturally dried leaves

there were more oval-shaped oil droplets

with the diameter of 0.29-1.04 μm

the number of units per unit area was 1-5 pieces/μm2

and the extraction rate of volatile oil and the content of D-borneol were 2.20% and 97%

respectively (P<0.05). In the constant temperature blast drying leaves

there were a large number of square or rectangular oil droplets in parenchyma cells

the extraction rate of volatile oil was significantly higher than 29.28% of naturally dried ones (P<0.05). In the vacuum drying leaves

there were a large number of irregular or oval oil droplets in parenchyma cells

the number per unit area was significantly higher than that of naturally dried ones (P<0.05)

the extraction rates of volatile oil and D-borneol were 23.42% and 0.63% and significantly higher than that of naturally dried ones. In the vacuum freeze drying leaves

there were a lot of intracellular circular oil droplets and the largest number of unit area

and the extraction rates of volatile oil and D-borneol were significantly higher than that of natural drying

which were 56.76% and 1.44%

respectively. Conclusion: Different drying methods have a great influence on the number of oil droplets

the extraction rate of volatile oil and the content of chemical compositions. The effect of vacuum freeze drying is the best

which is followed by vacuum drying

constant temperature blast drying and natural drying. Natural C. camphora camphor industrialized constant temperature drying method is feasible through the comprehensive analysis of equipment investment

production costs and drying effect.