Effect of deposition site condition on the growth process of electroless CoNiP films was investigated by employing the intermediate ＇treatment＇ step during the deposition. The effect of chemical species in the bath on the deposition sites, i.e., the film growth process, was examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). By changing the pH of the solutions for the ＇treatment＇ step, it was found that the ＇treatment＇ with higher pH solution resulted in the formation of smaller grains which possess lower perpendicular coercivity, Hc(perpendicular to). From these results, ammonia in the deposition bath results in the inhibition of the growth of crystallites, which leads lower Hc(perpendicular to). Based upon this, a model of the growth process of the CoNiP films was proposed.