Transmission　electron　microscope　is　widely　used　to　investigate　the　defects　induced　by　heavy　ion　irradiation　and　deuterium　plasma　exposure　in　tungsten,　however,　results　differ　greatly　between　in　situ　and　near-bulk　irradiation　experiments.　Here　we　adopt　the　back-thinned　electropolishing　and　re-electropolishing　method　to　study　the　microstructure　in　the　peak　damage　region　of　heavy　ion　damaged　tungsten.　Transition　from　dislocation　loops　to　complex　dislocation　tangles　with　increasing　damage　level　is　observed,　and　dislocation　tangle　decomposition　and　deuterium　bubble　formation　under　high-flux　deuterium　plasma　exposure　are　also　revealed.　The　results　presented　in　this　paper　provide　useful　information　for　further　investigation　on　irradiation　defect　evolution　and　the　synergetic　effect　of　displacement　damage　and　deuterium　behavior　in　W.