3-D model of small scale reactors for methanol steam reforming (MSR) with residual heat recovery was established. Five types of fins with different structures, such as straight fins, wavy fins, staggered wavy fins, perforated wavy fins and intercostal staggered wavy fins were designed for heat transfer enhancement in the heating channel. The influence of heating air flow rate, fins and its type on the performance of reactor were analyzed by CFD method. The results showed that the increasing of the air flow rate in the heating side was beneficial to methanol conversion, but its increment was more obvious by the way of enhancing heat transfer with fins. In addition, type of wavy fins had better heat transfer performance than that of straight fins due to its larger area and the ability of promoting airflow disturbance. Among the other four types of designed wavy fins, the intercostal staggered wavy fins have the best improvement on heat transfer performance, and its air temperature distribution is the most uniform in the heating side, its methanol conversion is also the highest. (C) 2019 Elsevier Ltd. All rights reserved.