In this paper, the 5-hydroxymethylfurfural (HMF) contents of the acacia honeys after heat treatment were determined by HPLC; the kinetics of HMF formation was also investigated. The HMF content of acacia honey was $0.38{pm}0.01$mg/kg, but rapidly increased to the maximum of $18,320.07{pm}14.29$ mg/kg at $190^{circ}C$ and decreased to $1,180.24{pm}6.54$ mg/kg at $230^{circ}C$ after heating. The HMF content increased gradually in honey samples heated in 12 h at the temperature of 80, 100, and $120^{circ}C$. The apparent frequency constant was $k_f=3.91{ imes}10^{25}/h$, and the apparent activation energy was $E_a$=173.10 kJ/mol. The HMF content in the acacia honey was related to honey composition, heating temperature, and time, and the HMF formation could also be related to the initial honey pH.