The structure of indium trihydroxide In(OH)3 for ITO(Indium Tin Oxide) has been analysed, the Madelung constant and lattice energy of In(OH)3 have been calculated, they are 2.9488 and -509521kJ/mol respectively, and a surface energy approximative expression is given, and then ulteriorly In(OH)3 crystal granule parameters are calculated in preparing nanosized In(OH)3 powder using the method of chemical precipitation,the growth rate 0.012nm/s about is given in this paper.