The nucleation and the crystal growth rates of Ge-Se-Te chalcogenide glass by two step heat-treatment and its effect on the mechanical optical properties and water-resistance were determined. The maximum nuclea-tion and crystal growth rate were 2.1$ imes$103/mm3 .min at 28$0^{circ}C$ and 0.4${mu}{ extrm}{m}$/min at 33$0^{circ}C$ respectively. When the crystal volume fraction with crystal size $1.5mutextrm{m}$ was about 4% the (hardness and fracture toughness were about 117kg/mm2 and 6.0 MPa.mm1/2)respectively. The weight loss of crystallized glass in water was lower than parent glass($25^{circ}C$ for 32 hrs : 0.03% 8$0^{circ}C$ for 16 hrs : 0.1%) as 0.01% at $25^{circ}C$, 0.03% at 8$0^{circ}C$ for 16 hrs : 0.1%) at $25^{circ}C$ 0.03% at 8$0^{circ}C$ respectively. The IR-transmittance decreased with increasing crystal size and crystal volume fraction. The IR-transmittance of crystallized glass with the crystal size of $1.5mutextrm{m}$ (crystal volume fraction : 4%) presented 56% which was about 4% lower than that of parent glass.