The invention discloses a gas path fault diagnostic method for a marine gas 
turbine based on a fuzzy 
Petri net (FPN), comprising the following steps of: (1) obtaining the operating standard value of the marine gas 
turbine; (2) based on an actually-measured value, calculating the membership grade of the actual operating parameter deviation belonging to the criterion deviation 
fuzzy subset by using a 
membership function; (3) defining the FPN in response to the characteristics of the fault diagnostic 
Petri net after determining the operating standard value and the deviation; and (4) determining a FPN 
reasoning algorithm for gas path fault diagnosis for the marine gas 
turbine based on related definitions of the transitional enabling and igniting rules. Through the gas path fault diagnostic method for the marine gas turbine based on the fuzzy 
Petri net (FPN), the defects of not strong university, wrong judgment and reasoning of the traditional method are overcome; it is actually proved that the problems of fuzziness and nondeterminacy in an gas path fault can be effectively solved by the gas path fault diagnostic 
algorithm for the marine gas turbine established by the gas path fault diagnostic method disclosed by the invention.