The rectangular channel louvered-fin compact heat exchanger (LFCHE) is the most efficient heat exchanger fin that has been used as a radiator fin. However, with this sort of heat exchanger, the pressure drop rises by three to four times as the heat transfer increases, which results in decreased performance. This research is aimed to numerically investigate the louver edges (vertical, inclined, and horizontal) and slant angle effect on the performance of LFCHE at different louver angles with air inlet velocity ranging from 1-30 m/sec (97 < 𝑆𝑓 𝑚𝑞 < 2917), using CFD. Selection of the computational domain, mesh independence test and validation of the base model with previous work was done before the investigation. First, the edge effect and then the slant angle effect was investigated and compared with the base (inclined edge) model. Totally 24 domain models were made. The result revealed that horizontally edged LFCHE decreased the pressure drop up to 24.2 % with a 1.01% increase in the outlet air temperature over the base (inclined edge) model. Thus, compared to the pressure drop, the temperature change is slighter effective on the louver edges. Based on the criteria for performance evaluation (PEC), the horizontally edged depicted a higher performance as compared to other louver edges, and at 10m/sec (𝑆𝑓 𝑚𝑞 = 972.33) the horizontal edge increases the volume goodness (jf) factor up to 21.49% over the base model. Moreover, for all louver angles, the horizontal edge behaves best jf-factor. Better performance was recorded for the horizontally edged fin at a louver angle of 24° at low 𝑆𝑓 𝑚𝑞 and 20° at high 𝑆𝑓 𝑚𝑞 which increased the jf-factor by 22% and 25%, respectively. The effect of slant angle was investigated based on the best-performed edge and the result revealed that at a slant angle of 6° the jf-factor increased up to 13.89 % at a low 𝑆𝑓 𝑚𝑞 . Moreover, it was seen that the slant angle effect was less significant on the performance at a high 𝑆𝑓 𝑚𝑞 . Generally, the horizontally edged and slanted LFCHE has a great performance in cooling the coolant with a minimum pressure drop on the air side. Keywords: Compact heat exchanger, friction factor, louver edge effect, louver fin, slant angle, volume goodness factor