Pentium FAN PROTONI spot welding machine made in Austria is a common equipment in the maintain of automobile body parts in the national vocational college skills competition. However,once functional fault occurs in use,the machine needs to be sent to Austria for maintenance,which brings great inconvenience to the competition. Through plenty of practical analysis and research,the basic structure and working principle of this machine are mastered,and three kinds of fault phenomenon are analyzed,which are selfinspection display NO RUN and welding spot without nugget,self-inspection RUN and welding spot without nugget,three-phase air switch trip after boot,the corresponding maintenance methods and specification operating requirements are summarized,which saves time and money.