Abstract： Objective： To analyze the administration rules of oral prescription of Chinese herbs for malignant pleural effusion(MPE) in lung cancer. Methods： By retrieving the three databases of China National Knowledge Internet， Wanfang Data and VIP， the literature on the significant curative effect of Chinese herbs on MPE in lung cancer in the 20 years from January 1，2000 to December 31，2020 were collected and collated， and the oral prescriptions were screened out. Through the descriptive analysis method of Traditional Chinese Medicine Inheritance Assistance System V2.5，the application frequency of the Chinese herbs and the frequency of the four qi， five favors and meridian entry were counted； the common and core Chinese herbal combinations were analyzed by Apriori analysis method； the potential new prescriptions for MPE in lung cancer were deeply mined through data analysis method of complex system entropy clustering. Results： A total of 60 prescriptions were screened， including 134 Chinese herbs. Among the Chinese herbs， a total of seven Chinese herbs had the application frequency of more than 40% ， namely Poria， Semen Lepidii， Semen Descurainiae， Rhizoma Atractylodis Macrocephalae， Radix Astragali， Fructus Jujubae， Radix et Rhizoma Glycyrrhizae， and Ramulus Cinnamomi. The Poria was the most frequently used， accounting for 71.67%. The four qi of Chinese herbs were mainly cold (260 times)， followed by warm(221 times). The five flavors were mainly sweet(417 times)， followed by bitter(274 times) and acrid(209 times). The meridian entry was mainly lung meridian(389 times)，followed by spleen meridian(303 times)， stomach meridian(244 times) and kidney meridian(179 times). With the assistance degree of 30% and confidence degree of 0.9，a total of 30 common herbal combinations were obtained，including seven Chinese herbs，namely Poria，Semen Lepidii，Semen Descurainiae，Rhizoma Atractylodis Macrocephalae， Radix Astragali， Fructus Jujubae， Radix et Rhizoma Glycyrrhizae， and Ramulus Cinnamomi. With the assistance degree of 50% and confidence degree of 0.9， one common herbal combination was obtained， including three Chinese herbs， namely Poria， Semen Lepidii and Semen Descurainiae， which belonged to water- draining and swelling- dispersing medicinals， coughsuppressing and panting-calming medicinals and qi-tonifying medicinals respectively. Through the entropy cluster analysis of complex system， eight core herbal combinations with high frequency and four new prescriptions were obtained. Conclusion：The treatment of MPE in lung cancer should be mainly focused on supplementing deficiency and reinforcing healthy qi， and boosting qi and promoting urination， and combined with resolving toxin and fighting against cancer，and dissolving phlegm and dissipating masses. The treatment can be combined with other treatment methods at the same time according to the characteristics of clinical symptoms and severity of the disease，such as the method of dissipating cold and resolving fluid retention with acid-warm medicinals and the method of regulating qi and fortifying spleen to move water.