Composting of the solid waste generated in large amount in a short time interval from olive industry environmentally very attractive due to increasing its value. On the other hand various authors showed that the characteristics of humic acids depend on the parent material they are extracted of, in addition to many other factors including composting conditions and geographical region. In the present work four samples of pure solid olive mill waste (olive cake) was naturally composted under four different atmospheric conditions without addition of any plant residues or any nutrients, for more than one year. Humic acids (HAs) were extracted from the composts and they were characterized by elemental analysis, FTIR, UV-visible spectroscopy and titration for reactive groups. The results show that the compost prepared as a compact small sphere of diameter 20cm and kept in door at room temperature for more than one year gives a reduced form of humic acids of high maturity, high aromatic content, high carboxylic and phenolic contents and highest chelating ability for Cu⁺² ions when compared with the results of five literature concerning commercial humic acids, The results of biological activity tests indicate in vitro, good antioxidant and anti bacterial activity, also exhibited mild antitumer but weak antiviral activity.