Abstract: The size of the coffee particles directly affects the quality of the finished coffee, therefore, efficiently identifying the size of the coffee powder particle size is particularly important for the identification of coffee quality. In the range of 89 μm ~140 μm, the laser-induced voltage (LIV) technology was used to detect the Yunnan small-grain coffee powder with different particle sizes. The coffee powder with different particle sizes exhibited different LIV responses, and its signal amplitude, response time, half-width, and other parameters were significantly different. As the particle size of the coffee powder gradually increased, the LIV signal decreased first and then increased to a minimum of 104 μm~107 μm. The response time and half-width of the signals also varied with the particle size, with positive and negative correlation, respectively. The results show that the laser induced voltage technology is more sensitive to changes in the particle size of the coffee powder, which is expected to be an effective detection method for the particle size of the coffee powder.