Abstract: Breakage can normally be induced by the impact of granular materials and mechanical equipment on agricultural products during seed discharging, harvesting, transportation, and crushing processes. Some breakage can damage the products, such as seed discharge and transportation, whereas, another breakage can be meaningful, such as crushing. Therefore, it is a high demand to investigate the breakage characteristics of product granules for the decision-making on the operational parameters of agricultural machinery, including the transportation, seeding, and crushing. Taking the maize kernel as the research object, the main purpose of this study is to clarify the influence of moisture content and impact speed on the impact breakage characteristics of products. Five types of maize kernel samples were first prepared with the variable moisture content. An impact testing device was designed for the single particle. A series of impact tests were performed on the maize kernels with five moisture contents. The breakage characteristics of the maize kernel were then characterized, in terms of breakage patterns, the extent of breakage, and the critical impact velocity. The experimental results revealed that the broken particles of maize kernels after breaking were divided into three levels of breakage patterns: the unbroken, rupture, and fragmentation, according to the size and quantity distribution characteristics. Among them, the fracture pattern included the overall and local rupture. The maximum particle mass ratio (W) was defined as the indicator for the breakage patterns of maize kernels, where the W was the mass of the big particle in the broken particles to the mass of the maize kernel. The regression equations were established between the W value and impact velocity of maize kernels with different moisture content, where the coefficients of determination (R2) were obtained all greater than 0.92. The critical rupture velocities of maize kernels with the moisture content from low to high were determined to be 11.45, 15.54, 19.84, 30.49, and 34.28 m/s, respectively, and the critical fragmentation velocities were 19.55, 23.75, 28.68, 42.07, and 46.79 m/s, respectively, according to the regression equations. It indicated that the critical rupture velocity and critical fragmentation velocity of the maize kernel increased with the increase of moisture content. The extent of breakage of maize kernels was characterized by the average particle size of broken particles. The 2FI model regression equation of average particle size was established with the impact velocity and moisture content using the response surface method (RSM), where the R2 was 0.96. In addition, the analysis of variance showed that there was an extremely significant influence on impact velocity, the moisture content of maize kernels, and the interaction on the extent of breakage (P<0.01). The extent of breakage of maize kernels increased with the increase of impact velocity, while decreasing with the increase of moisture content of maize kernels. These datasets can be used to determine the operational parameters of agricultural equipment during granule processing. The finding can also provide a theoretical basis for the impact breakage characteristics of agricultural products.