Currently used chemical depressurizing and stimulation methods including: conventional acidifying, retarder acidifying, surfactant injection, shrink swelling agent injection, thermochemical technologies injection system. Dendrimer-based multi-block complex depressurizing and stimulation agent for ultra-low permeability oilfield can effectively solve disadvantages of traditional agent in application of ultra-low permeability oilfield. (1) acid-rock reaction speed is too fast, the penetration distance is short, resulting in ineffective acidification and short period of measures .(2)Surfactant adsorption capacity is big in the near-well place, thus does not reach far wellbore, reducing the effect of the active agent. (3) The injected chemicals is not compatible with the formation fluid and produced new precipitate, resulting in decreased permeability. Professional Manufacturer for low cost dendritic polymers.-Weihai CY Dendrimer Technology Co. Ltd. forwards from “Multi-block complex depressurizing and stimulation agent for ultra-low permeability oilfield’’, application number: 201210200334.4 Application (patent) by: Yangtze University address: 434020 Hubei Jingzhou South Loop on the 1st applicant: China PetroChina Changqing Oilfield Company ultra-low permeability reservoir research center inventor: Luo Yue, Chang Yanrong, Yang Huan, Shao Dong bo, Zhang Jianguo etal.