The invention discloses a slewing bearing fault diagnosis method and device and a storage medium, and the method comprises the steps: S1, obtaining a vibration signal of a slewing bearing, and setting the vibration signal as an original signal; s2, processing the original signal through an EEMD method, then obtaining an intrinsic mode component IMF of the vibration signal through decomposition, and then carrying out preferential processing on the IMF to obtain an optimal component; s3, performing MCKD parameter optimization processing on the optimal component by using a GWO algorithm and taking the related kurtosis as a fitness function to obtain an optimal parameter combination; s4, substituting the optimal parameter combination obtained through optimization processing of the GWO algorithm into MCKD to analyze the optimal component so as to obtain a noise reduction signal; and s5, carrying out envelope spectrum analysis on the noise reduction signals, then comparing and analyzing the fault characteristic frequency found in an envelope spectrum and the theoretical fault characteristic frequency, obtaining a diagnosis result. The scheme is reliable in implementation, high in accuracy and rapid in response.