In response to the problem that when conventional chelating plugging removal agents are used in acidizing plugging removal operations in oilfields, the chelates produced after dispersing scale substances are insoluble and prone to block the reservoir, polyamino polyether methylene phosphonic acid (PAPEMP) and 2 - phosphonobutane - 1,2,4 - tricarboxylic acid (PBTCA) were used as the key main agents, and hydrofluoric acid (HF) and dimethyldiallylammonium chloride (DMDAAC) were compounded to prepare a non - precipitating organic phosphine chelating plugging removal agent PPF (including pre - acid PPF - A and main acid PPF - B). Through pH tests, marble corrosion experiments, corrosion experiments of on - site scale samples and cuttings, experiments on measuring the corrosion rate at different times, and experiments on inhibiting the secondary precipitation of calcium fluoride, the physical and chemical properties, scale dissolution ability, slow - rate deep penetration performance, and precipitation inhibition performance of the PPF system were systematically evaluated. The results show that: the pH values of PPF - A and PPF - B are 1.40 and 3.40 respectively, which are significantly higher than those of conventional inorganic acids at the same concentration; PPF - A has a large corrosion amount on marble (calcium carbonate) (the mass difference of corrosion in 24 h reaches 5.78 g), and the mass difference after filtering through quantitative filter paper is positive. The solution is clear to the naked eye, and no calcium chelate precipitation is produced; the corrosion rate of PPF - A on on - site scale samples reaches 57.36%, which is 81% of the corrosion ability of hydrochloric acid with a mass concentration of 10%; the corrosion rate of PPF - B reacting with on - site sandstone cuttings for 24 h is 24.23%, and the corrosion rate continuously increases with the reaction time (2 - 24 h), showing good slow - rate deep penetration performance; the compound system with PAPEMP and PBTCA as the main agents can effectively inhibit the secondary precipitation of calcium fluoride within 72 h, the solution remains clear, and the theoretical inhibition rate reaches 95.87%. This plugging removal agent has the advantages of high pH value, moderate corrosion ability, slow - rate deep penetration, and long - term inhibition of secondary precipitation. It is suitable for oilfield acidizing plugging removal operations to prevent the destruction of the reservoir skeleton and pipeline corrosion, achieve deep slow - rate plugging removal, and improve the difficulty of produced fluid treatment, and can avoid the pollution of the reservoir caused by the precipitation of calcium fluoride or chelates.