The invention discloses a method for diagnosing the type of leakage of a drilled well based on the neural network fusion technique. The method for diagnosing the type of leakage of the drilled well based on the neural network fusion technique comprises the following steps that S1, a fusion neural network structure is determined, and a well leakage type diagnosis parameter space is established; S2, data are preprocessed; S3, data which are normalized are input into all neural networks; S4, data infusion is conducted on output values of all the neural networks according to multiple neural network fusion algorithms and then a well leakage type diagnosis result is obtained finally. The step S1 comprises the sub-steps that S11, the fusion neural network structure is selected; S12, network training is conducted; S13, the networks are checked, and the well leakage type diagnosis parameter space is established. According to the method for diagnosing the type of leakage of the drilled well based on the neural network fusion, the multiple neural networks are used for processing data, the multiple neural network output results are processed through the data fusion algorithm, the performance is high, and the result is highly reliable.