The　evolutions　of　conventional　soliton　(CS)　and　breathing　soliton　(BS)　dynamics　in　an　anomalous　dispersion　Er-doped　fiber　laser　are　investigated　experimentally　and　numerically.　Based　on　the　dispersive　Fourier　transform　technique,　the　evolution　processes　of　CS　buildup　and　extinction　are　observed　and　discussed.　It　was　found　that　a　transitional　unstable　stage　exists　during　the　buildup　and　extinction　process.　In　the　same　laser,　BS　state　is　also　reached.　Simulation　results　of　CS　and　BS　evolutionary　dynamics　are　anastomotic　with　experimental　results.　The　results　may　contribute　to　better　understanding　of　the　complex　pulse　dynamics　in　ultrafast　fiber　lasers.