A 3D finite element (FE) model is built to numerically analyze heating parameters on temperature during brazing diamond grains by the pulsed laser spot heating. A pulsed Nd:YAG laser is used for experimental validation. The results show that during laser heating, the temperature varies periodically because of the pulsed heat flux. Four key thermal indices, the maximum temperature Tmax, the minimum temperature Tmin, the average temperature Tav and the temperature fluctuation amplitude ΔT are addressed. The primary factor affecting Tmax, ΔT and Tav is the pulse power and on Tmin is the pulse frequency. The secondary effect factor on Tmax, Tav and ΔT is the pulse width and on Tmin is the pulse power. For engineering practice, the order of designing heating parameters is recommended as: Pulse power, second frequency and last width.