The invention discloses a testing method for offshore oil-gas well cooperative decision. The test method comprises the following steps: S1, designing a distributed knowledge base; S2, sharing and integrating test data; S3, performing statistics by combining built-in software and system with numerical calculation, and performing cross interchange on a knowledge base and numerical calculation resultdata; S4, establishing a model of the fluid along the wellbore, and establishing mass conservation, momentum conservation and energy conservation models in sequence from the bottom of the well, the seabed, the wellhead and the ground flow; s5, carrying out real-time linkage decision making on oil reservoir geology and test engineering as well as a land base and an offshore site. Whole-course visualization of offshore oil and gas well testing, integration of oil reservoir geology and testing engineering and real-time collaborative decision making of a land base and an offshore site are achieved, and the problems that professional communication is not smooth, and decision making efficiency is low in offshore oil and gas well testing operation decision making over the years are solved.