The Nd:YAG nanopowders were synthesized at 800-1300 degrees C via a modified co-precipitation method. Nd:YAG transparent ceramics were fabricated by vacuum sintering at 1770-1790 degrees C for 20 h with heating rates 1-10 degrees C/min. The effects of calcining temperatures of highly sinterable Nd:YAG nanopowders, sintering temperature and heating rate on microstructure and transmittance of Nd:YAG ceramics have been investigated. After calcination at 1250 degrees C for 4 h, Nd:YAG nanopowders with primary particle size of about 106 nm and low agglomeration were obtained. Using as prepared powders, high optical quality Nd: YAG ceramics prepared at 1780 degrees C with dwell time of 20 h and heating rate at 1 degrees C/min have been obtained and shows the in-line transmittance reached 83.9% (1064 nm). With 17.6W of maximum absorbed pump power, laser output of 4.5W has been obtained with an oscillation threshold and a slope efficiency of 0.5W and 25.6%. (C) 2015 Elsevier Ltd. All rights reserved.