  We explore the Quasi-Periodic Pulsations (QPPs) in a solar flare observed by
Fermi Gamma-ray Burst Monitor (GBM), Solar Dynamics Observatory (SDO), Solar
Terrestrial Relations Observatory (STEREO), and Interface Region Imaging
Spectrograph (IRIS) on 2014 September 10. QPPs are identified as the regular
and periodic peaks on the rapidly-varying components, which are the light
curves after removing the slowly-varying components. The QPPs display only
three peaks at the beginning on the hard X-ray (HXR) emissions, but ten peaks
on the chromospheric and coronal line emissions, and more than seven peaks
(each peak is corresponding to a type III burst on the dynamic spectra) at the
radio emissions. An uniform quasi-period about 4 minutes are detected among
them. AIA imaging observations exhibit that the 4-min QPPs originate from the
flare ribbon, and tend to appear on the ribbon front. IRIS spectral
observations show that each peak of the QPPs tends to a broad line width and a
red Doppler velocity at C I, O IV, Si IV, and Fe XXI lines. Our findings
indicate that the QPPs are produced by the non-thermal electrons which are
accelerated by the induced quasi-periodic magnetic reconnections in this flare.
