Production of essential oils from plants for usage in pharmaceutical and cosmetic industries has been developed in some industrial countries, but in Iran we have been importing these essential oils with high cost. One of these valuable essential oils which has many application in food, pharmaceutical and cosmetic industries in the lavender essential oil. The major components of the lavender essential oil are fenchone, camphor, linalool, linalyl acetate. The advantage of Iranian lavender is that approximately 80% of the essential oil is comprised of fenchone, camphor, linalool, linalyl acetate. While the foreign lavender contained either linalool and linalyl acetate or fenchone and camphore. The objective of this project was the supercritical fluid extraction of essential oil from Iranian lavender flower with two methods of semi continuous and new procedure of periodic static-dynamic. Also the soxhlet method was used as a parallel method for the determination of extraction yield. In this study, statistical experimental technique base on “Central Composite Design” was applied in order to optimize operation conditions, the effect of important parameters on extraction efficiency such as supercritical pressure, temperature, dynamic time, and static time were investigated in the range of 80-120 bar, 40-60 oC, 80-120 min, and 10-30 min, respectively. The optimum operative condition in the semi continuous method to obtain 90% extraction yield using five surface- four factors were as follows: 49 oC, 112 bar, 123 min, and 22 min. The optimum operative condition in the new periodic static-dynamic method to obtain 94.4% extraction yield using three surface-3 factors with Box-Behnkon are 49 oC, 110 bar, and 8×15. Considering the aforementioned results, the yield of new method is higher and also solvent, pump energy, and circulating cooler energy with respect to semi continuous method have decreased up to 250%. In the semicontinuous and periodic static-dynamic method the adjusted R2 for the percent of oil yield was 85.1 and 96.8, respectively. This means that the developed model instability was 14.9, 1.4 and also the linear regression coefficient (R2) was obtained to be 92.1 and 95.9. The least extraction time and low solvent consumption (environmentally compatible) are the advantages of supercritical fluid extraction. Furthermore, the efficiency of SFE is comparable to Soxhlet method in which a toxic, flammable, expensive,