There is large number of small-sized reservoirs and widely distributed in mainland of China, but most of them short of management or the security situation is grim. Once the dam break, the loss caused by damage is very serious. Therefore, it is very necessary to look for a general assessment method to monitor the reservoir safety and avoid dam-breaking accident timely. Currently, the common method for reservoirs risk assessment is a traditional approach based on Certainty Criterion, this method can give the overall safety degree by qualitative assessment, which need a large number of monitoring data and mainly suitable for large and medium sized reservoirs. However, vast majority small-sized reservoirs were neglected and had no monitoring equipment, went short of operation statistical data, so it is difficult to assess using the traditional Certainty Criterion. Aiming at the characteristics of small-sized reservoirs, in this paper we proposed the fuzzy AHP assessment method suitable for small-sized reservoirs' risk analysis, which is based on statistics analysis of the wracked small-sized reservoirs and effective identification of risk factors, then verified the applicability and effectiveness of this method by two engineering cases. The result show that this method can be more truly reflect the security status of the reservoir, and also has the reference value and application prospect for dangerous reservoirs reinforcement in future.