A tunnel drying equipment was used to simulate the industrial tunnel oven and determine the drying characteristics of Cantonese almond cookie. Scanning electron microscopy (SEM) followed by image analysis were done to determine the pore microstructure of almond cookie. The effect of particle size on the drying properties and quality of Cantonese almond cookie was explored based on fractal theory. The results showed that the almond cookie with low moisture content had an internal porous structure and an apparent fractal feature. The smaller the particle size was, the more complex the pore structure was. Under the same baking temperature of 100 ℃ or 120 ℃, the drying rate of almond cookies made of 140-mesh powder were significantly higher than that of almond cookies made of 60-mesh and 100-mesh powders. Texture property analysis (TPA) indicated that with a decrease in particle sizes (60 mesh→100 mesh→140 mesh), the hardness, cohesiveness, and chewiness of almond cookies decreased significantly (p<0.05). According to the sensory evaluation, the almond cookie made of 140-mesh powder had better quality than those made of 60 mesh and 100 mesh. Therefore, the drying rate and quality of Cantonese almond cookie can be improved by reducing particle size within a certain range during the production of almond cookie powder.