For the past few years, thermosensitive hydrogels have been widely used in biomedical field including drug delivery system, tissue engineering and so on. Thermosensitive hydrogels formed with micelles assembled by amphiphilic block polymer based on polyethyleneglycol (PEG) and biodegradable polyesters play an important role among these hydrogels. In the present review, we summarize the effects of molecular weight, sequence of segments, ratio between hydrophilic and hydrophobic block and structure of hydrophobic block on the thermosensitive behavior of aqueous solution of amphiphilic block polymer synthesized by PEG and ε-polycaprolactone. The progresses of the thermosensitive hydrogel in the local drug delivery are also explored.