The compression behavior of natural adamite [Zn2AsO4OH] has been investigated up to 11.07 GPa at room temperature utilizing in situ angle-dispersive X-ray diffraction and a diamond anvil cell. No phase transition has been observed within the pressure range investigated. A third-order Birch-Murnaghan equation of state fitted to all of the data points yielded V (0) = 430.1(4) a"<<(3), K (0) = 80(3) GPa, K' (0) = 1.9(5). The K (0) was obtained as 69(1) GPa when K' (0) was fixed at 4. Analysis of axial compressible moduli shows the intense compression anisotropy of adamite: K (a0) = 37(3) GPa, K (b0) = 153(6) GPa, K (c0) = 168(8) GPa; hence, a axis is the most compressible and the compressibility of b and c axis is comparable. Furthermore, the comparisons among the compressional properties of adamite, libethenite (Cu2PO4OH, also belongs to olivenite group), and andalusite (Al2SiO4O has the similar structure with adamite) at high pressure were made.