Abstract: We develop a tunable diode laser absorption tomography algorithm for two-dimen-sional (2D)temperature reconstruction based on orthogonal optical paths.In order to evaluate the reconstruction method,we analyzed the 2D reconstruction results of two different tempera-ture phantoms by means of numerical simulation of N×N uniform grid arrangement consisting of 2N (N≥3)light of sight (LOS)measurement path.The maximum deviation and the mean devi-ation were defined to describe the effect of the value of N on the reconstruction results.The re-sults show that for the single symmetrical peak non-uniform temperature phantom,the maxi-mum deviation of the reconstruction temperature is less than 50K(2.5%),the maximum devia-tion fluctuates with N parity and the overall trend is decrease with N increasing.The mean devia-tion is reduced as N increases,which means the reconstruction is better with N increasing.But when N≥9 ,the improvements are not distinct any more.For the bimodal temperature phantom, the maximum deviations of the results using this 2D reconstruction method are more than 350K (15.2%)and the mean deviations are greater than 0.03.What’s worse,there is a serious distor-tion.However,the reconstruction results can be improved by added measurement path diagonal-ly across the tested temperature field.The study is helpful for the real 2D measurement system setup and actual application.