Workers on construction sites are exposed to multiple and varied threats. Of those, climatic factors such as high/low air temperatures and high/low humidity have a bad mental and physical health effect on workers. Especially, work in hot environment has a tendency to cause fatigue, reduce productivity and increase the incidence of accident. So, the purpose of this research was to understand working clothes and working environment of workers at a construction site in summer. The depth interview was performed by 45 workers of 4 different construction sites and the results were as follows. Workers wore average 4 items as clothing(upper, lower) and average 5 items as personal protective equipments(PPEs). They answered "head" is the hottest body area and must be protected during working. This means the necessity of development in safety hat. In addition, it should be developed working clothes and gaiters for alleviating heat stress and safety shoes for diminishing weight. It is expected that this research plays basic and important rolls to develop PPEs for reducing the heat stress of construction workers.