The invention relates to a blade inherent frequency automatic testing system which comprises an external control analysis system, a base, a stepping motor, a rotating disc, a clamping assembly, a laser displacement sensor and a jetting assembly. The stepping motor drives the rotating disc to axially rotate so as to drive the to-be-tested blade to rotate; the jetting end interruptedly injects the gas at equal time to enable the to-be-tested blade to vibrate, and meanwhile, the vibration displacement of the to-be-tested blade is measured through the laser displacement sensor, and the obtained vibration displacement information and the vibration frequency information are transmitted to the external control analysis system, so that the inherent frequency of each order of the to-be-tested bladeis obtained. The middle test process does not need manual intervention, the automation degree is high, the requirement for the technical level of an operator is low, and the testing efficiency is high. The technical level and the testing efficiency of related industries can be greatly improved, and the application prospect is good.