The invention provides an ultra-high-water-content oil field exploitation early-warning method. The method comprises: step 1, screening indexes affecting production decline in at a relatively large degree and taking the indexes as early-warning indexes according to analysis of influence factors consisting of the yield; step 2, establishing an early-warning index standard, determining an abnormal fluctuation range of the indexes with consideration of influence of change of the early-warning indexes on the yield, and taking a dividing value of normal fluctuation and abnormal fluctuation as an early warning threshold value; and step 3, analyzing influence of the early-warning indexes on an oil field development yield through mine field statistics and theory calculation, and determining different syntagmatic relations of early-warning indexes with three early-warning levels of red, yellow, and green by utilizing matching relations among the indexes. By using the method, early-warning of a development condition of an old ultra-high-water-content oil field well in the next year can be realized through the matching relations among the early-warning indexes.