NOVELTY - Producing theophylline comprises selecting green tea leaves as a raw material and then crushing into 0.5 meshes powder, drying and roasting the powder, adding iron monomer and natural alkaloid to the powder, stirring the mixture, baking and heating the mixture at 30 degrees C for 20 minutes, holding and roasting the mixture, separating and oxidizing the mixture, condensing and extracting the mixture, processing and baking the mixture, adding clean water to the mixture, heating the mixture, adding alkali to the mixture, boiling and extracting the mixture, packaging the mixture, and storing.    USE - The method is useful for producing theophylline (claimed), which is useful for a medicine, a food additive and healthcare products, and in agricultural industry.    ADVANTAGE - The method conveniently produces the theophylline with high purity of 98.2-99.92% and reduced energy consumption in an eco-friendly manner, and does not harm to human body.    DETAILED DESCRIPTION - Producing theophylline comprises selecting green tea leaves as a raw material, crushing the raw material into 0.5 meshes powder, drying the crushed powder, roasting the dried powder, adding iron monomer and natural alkaloid to the roasted powder, uniformly mixing, stirring the mixture having a size of 800 mm, baking the mounted mixture at high temperature, heating the baked mixture at 30 degrees C for 20 minutes under high pressure, holding the heated mixture at 70 degrees C, roasting the mixture using a furnace for 1 hour, cooling the roasted mixture at 40 degrees C for 0.5 hours, holding the cooled mixture at 210 degrees C, heating the mixture at 40 degrees C for 4 hours using a pressure cooker, separating the heated mixture, raising the temperature, oxidizing the mixture, condensing the oxidized mixture, extracting the condensed mixture using clean water, processing the extracted mixture, baking the processed mixture, roasting the baked mixture using a pot having a diameter of 800 mm, adding clean water to the roasted mixture having a size of 60-800 mm, heating the mixture at 30 degrees C, adding 5 pts. wt. alkali to the heated mixture, stirring the mixture, boiling the stirred mixture, roasting the boiled mixture for 15 minutes, filtering the roasted mixture for 10 hours, naturally cooling the filtered mixture, condensing the cooled mixture at low temperature for 24 hours, squeezing the condensed mixture, drying the squeezed mixture using a drying machine, adding 60 pts. wt. clean water to the dried mixture, baking the mixture, heating the baked mixture at 40 degrees C, drying the heated mixture, stirring the dried mixture for 30 minutes, crushing the stirred mixture for 5-10 minutes, repeatedly filtering the crushed mixture, naturally cooling the filtered mixture, condensing the cooled mixture, crystallizing the condensed mixture, squeezing the crystallized mixture, drying the squeezed mixture at 60 degrees C, stirring the dried mixture for 30 minutes, removing impurities, heating the mixture, roasting the heated mixture at 90 degrees C for 5-10 minutes, stirring the roasted mixture for 10 minutes, extracting the stirred mixture, pre-heating the extracted mixture at 15 degrees C for 10 minutes, drying the heated mixture at 120 degrees C, baking the dried mixture for 40 minutes, rolling the baked mixture, packaging the mixture, and storing.