In this work we performed a detailed investigation about ordering in Ba3CaNb2O9 perovskite. The sintering temperature and time were changed to obtain samples with different ordering. The order parameters were probed by Raman spectroscopy based on a partial disordered model. To use the partial disordered model correctly we performed ab initio calculations in Ba3CaNb2O9 to assign the optical phonons. The results showed that sintering temperature improves order while sintering time is not so efficient to promote order. (c) 2013 Elsevier Ltd. All rights reserved.