The invention discloses a frequency converter and relates to the field of electronic parts. The frequency converter is characterized by comprising a temperature detection module, a central processingunit, a display module, and a computing detection module. Service times of the frequency converter corresponding to the corresponding temperature in the frequency converter are defined as T(1), T(2),T(3)... T(n); temperature corresponding to the standard service time of the frequency converter is X (standard); current temperature signal in the frequency converter detected by the temperature detection module (1) is M; first judgment function Y=|M-X(standard)|, first comparison parameter A (reference) and interference coefficient alpha of other factors upon the service time of the frequency converter under a current working environment are set in the computing detection module (4); the temperature detection module, the computing detection module and the first judgment function enable a worker to quickly know changes of the inner temperature of the frequency converter and corresponding service times, so that the worker can be reminded for changing the frequency converter.