In polymerflooding process, the poor solubility of polymer and the wrap of incompletely dissolvedpolymer particles with heavy oil lead to the generation of complicated blockage, which seriously affectsthe normal production of wells. Therefore, how to fabricate an effective blockage removal agent isparticularly important. Based on the blockage from Bohai Offshore Oilfield in China, a blockage removalagent composed of (0.5 wt% potassium persulfate + kerosene (the ratio of kerosene: blockage is 3:5)+0.3 wt% OP-10, the oil-water ratio is 1:9) was developed. The removal effect and mechanism werecharacterized by weight loss method and core test. Moreover, the emulsification property of the removalagent was also evaluated by microscopic appearance. The results showed that the blockage removal agentcan be formulated as an O/W emulsion and had good stability for more than 72 h. Core test showed thatthe permeability had a significant improvement after injection of removal agent. The emulsion-typeremoval agent can demulsify after contact with the blockage, then the oil-soluble detergent as internalphase in emulsion can be released which contributes to the wash off of heavy oil. Accompanied with thepolymer degradation by the oxidant, this agent realized the effective dissolution and removal of blockage.