Abstract: A newly seamless self-adaptive anti-jamming pump was developed to solve the problems of large amounts of leakage, low pump efficiency, great friction resistance, stuck pump and sucker rod breaking off frequently which resulted from the fouling easily deposited on the surface of pump barrel and plunger in oil well with Alkaline-Surfactant-Polymer (ASP) flooding. That device includes seamless self-adaptive plunger pump and seamless self-adaptive scraper. Hydraulic self-sealing principle and composite sealing structure were employed onto the plunger pump to realize low leakage volume, high pumping efficiency, little or no fouling and sand sticking; meantime, the spring structure was adopted to make that the scraper was self-adaptive to the pump barrel diameter and scraping seamlessly and effectively on the pump barrel section above the plunger, otherwise, fouling inhibition on-way valve can effectively prevents scale particles scraped by scraper from subsiding and flow out of the well with fluid. The field test showed that pump inspection period by using this device extended to 400 days from 50 days of the conventional plunger pump, the statistical average pump efficiency enhanced from 42.25% to 63.32%，improving economic benefits of oil well greatly.