The main challenge and limitation of combustion diagnosis technique lies in the volumetric/spatial resolution. Frequently reported technique widely use laser bean scanning to get inner knowledge of combustion, however due to the line-of-sight nature, spatial resolution along the “path” is lacked. With the ability of 3-D tomography detection, CTC technique (computed tomography of chemiluminescence) shows advantage over other techniques; but not yet widely used in combustion science study. In CTC measurement, “dense projection” is required to make satisfying tomography reconstruction, but this is practically hard to meet for high cost and spatial limitation. At sparse projection conditions, tomography reconstruction is distorted with the appearance of geometric blur. The reason of occurrence of blur is analyzed in this paper, and an improved method for tomography reconstruction is proposed. Test results show that blur distortion could be effectively eliminated using the improved method at sparse projection conditions. Other factors and constraints that have influence on flame tomography measurement are discussed in this paper, and quantitative evaluations were made through tests.