The invention discloses a determination method for a combination flooding efficient oil flooding scheme under the condition of a four-injection nine-mining well pattern and the combination flooding efficient oil flooding scheme. The four-injection nine-mining well pattern is suitable for a combination flooding preliminary test, numerical simulation software IMCFS with the more accurate mechanism and relatively perfect functions is adopted, and a simplified structural model capable of reflecting main geologic features of a test oil reservoir is built; and fitting is carried out on a combination flooding field test, the field oil flooding test is digitized, and a digital geologic model platform including oil-reservoir water flooding information and combination flooding information is built. The oil flooding scheme is calculated on the geologic platform, it can be called that the digital oil flooding test is carried out, oil flooding test study can be carried out more comprehensively and deeply, then basic indexes of the combination oil flooding scheme are optimized, and the combination flooding test optimized oil flooding scheme under the condition of the four-injection nine-mining well pattern is established.