  The ARGO-YBJ experiment is an extensive air shower array with full coverage
RPC detectors located at Yangbajing (4300 m asl, Tibet, China). It is operated
with high duty cycle (>86%) and a large field of view ($\sim$ 2sr). It
continuously monitors the entire overhead sky at $\gamma$-ray energies above
0.1 TeV. In the talk, we will present the result of the northern sky survey
(between declinations of -10$^{\circ}$ and 70$^{\circ}$) from an analysis of ~4
years of the ARGO-YBJ data (between July 2006 and February 2011). There are
four known TeV sources observed with significance greater than 5 S.D.. The
significance from Crab Nebula is more than 16 S.D.. 90% confidence level upper
limits to the flux from all directions in the sky are also presented, which
vary from 0.09 to 0.53 Crab unit for Crab-like point sources.
