In this research, a precipitation method was used to synthesize ${eta}-Ga_2O_3$ powders with various particle morphologies and sizes under varying precipitation conditions, such as gallium nitrate concentration, pH, and aging temperature, using ammonium hydroxide and ammonium carbonate as precipitants. The obtained powders were characterized in detail by XRD, SEM, FT-IR, and TG-DSC. From the TG-DSC result, GaOOH phase was transformed to ${eta}-Ga_2O_3$ at around $742^{circ}C$, and weight loss percent was about 14 % when $NH_4OH$ was used as a precipitant. Also, ${eta}-Ga_2O_3$ formed at $749^{circ}C$ and weight loss percent was about 15 % when $(NH)_2CO_3$ was used as a precipitant. XRD results showed that the obtained $Ga_2O_3$ had pure monoclinic phase in both cases. When $(NH)_2CO_3$ was used as a precipitant, the particle shape changed and became irregular. The range of particle size was about $500nm-4{mu}m$ based on various concentrations of gallium nitrate solution with $NH_4OH$. The particle size was increased from $1-2{mu}m$ to $3-4{mu}m$ and particle shape was changed from spherical to bar type by increasing aging temperature over $80^{circ}C$.