L-Ornithine-L-Aspartate (LOLA), a pharmaceutical, 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 was produced with controlling temperature and methanol concentration.