  In the third Fermi catalogue (3FGL) there are sixteen gamma-ray globular
clusters. After analyzing the recent released Pass 8 data of Fermi Large Area
Telescope (LAT), we report the discovery of significant gamma-ray emission from
M 15 and NGC 6397, confirm that NGC 5904 is a gamma-ray emitter and find
evidence of gamma-ray emission from NGC 6218 and NGC 6139. Inter- estingly, in
the globular clusters M 15, NGC 6397 and NGC 5904, millisecond pulsars (MSPs)
have been found in radio or X-rays, which are strongly in support of the MSP
origin of the gamma-ray emission. However, due to the relative low luminosity
of the gamma-ray emission we do not find any evidence for the gamma-ray
pulsation or flux variability of these sources.
