Abstract: After nearly 40 years of exploratory development, Jiyang Depression entered into mature development stage and its exploration targets are subtle reservoirs now which brought great difficulty for exploration.Though the successful rate of exploratory wells in Jiyang Depression is high, but there are nearly 50% wells failed or with low efficiency.According to the definition of unsuccessful exploratory well, based on 6 controlling accumulation factors such as source rock, reservoir, cap rock, trap, transportation and seal, failed well analysis method was built in terms of effective trap, existing reservoir, developed transportation system, and oil and gas fullness.Sand conglomerate, turbidite, beach bar and channel sand formations were the stimulation targets in Jiyang Depression in the "10th five year" plan, but they were not successful.Principal exploration risks of above-mentioned formation types were identified and risk aversion were proposed in this paper.