L-Ornithine-L-Aspartate(LOLA), a pharmaceutical material, has two crystal forms: a hydrate and an anhydrous form. The influence of the feeding rate, solvent concentration and temperature on the form of crystal was investigated in drowning-out crystallization that was carried out by two semi-batch methods. In this study, we attempted to unify results for the formation of polymorphs and LOLA with the desired anhydrous form could be produced with controlling temperature and methanol concentration.