Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
; Nanjing Univ, Dept Astron, Nanjing 210008, Peoples R China
We have calculated the generation parameters for known gamma-ray pulsars after allowing for observational effects. The calculated generation parameters show a good linear relation with the observed spectral indices. They are all numerically greater than 2.0, and we suggest that this fact can be used as a criterion for gamma-ray pulsar.