Abstract: Fusion triple product represents a crucial criterion for evaluating the potential of self-sustained fusion nuclear reactions. It employs the product of three physical properties: the fuel nuclei number density (n), plasma energy confinement time (\tau_\mathrmE) and fuel temperature (T) to determine the energy balance conditions for achieving self-sustained nuclear fusion. This study considers a fusion reaction system using ⁶Li-D as nuclear fuel, neglects cyclotron radiation, incorporates the impact of relativistic effects on bremsstrahlung radiation and the influence of energy recovery efficiency on the energy gain factor Q. Based on this foundation, the minimum triple product (n_\mathrmiT\tau_\mathrmE=4.9×10²³ m⁻³·keV·s) is calculated for the ⁶Li-D reaction to yield energy gain of Q=1. These results show that although the ⁶Li-D fusion reaction can achieve a positive energy gain but the condition required for the ⁶Li-D fusion reaction is more difficult than the D-T fusion reaction.