A novel micro combustor with block insert has been introduced in this work. The effect of block insert on wall temperature distribution and entropy generation of the micro combustor is investigated. The results indicate that the employment of a block insert can significantly increase the mean wall temperature and improve the uniformity of temperature distribution along the wall. When the gap length is 4.2 mm, the micro combustor can produce the highest mean wall temperature with the lowest entropy generation. (C) 2015 Elsevier B.V. All rights reserved.