Occupational exposure and risk assessment were conducted to evaluate the safety of operators when insecticide acetamiprid was applied to apple orchard using a speed sprayer. Dermal patches, cotton gloves, socks, and masks were used to monitor the dermal exposure, and personal air pump with solid sorbent was used to measure the potential inhalation exposure. In validation to analytical methods, the limit of detection and limit of quantitation were 0.25 ng and 1 ng, respectively. Good reproducibility (coefficient variation < 4%), linearity (coefficient determination > 0.999), and recovery (85.3-118.2%) were obtained. Trapping efficiency of solid sorbent was 96.4% while breakthrough did not occur. Only hand exposure was measured on the gloves during mixing/loading to give $33-1,132{mu}g$. Exposure amount of operator 3 among 4 workers was noticeably high. The total volumes of spray liquid for operators were $535-1,235mL{cdot}h^{-1}$, corresponding to 0.03-0.08% of the applied spray solution. Highest contaminated parts of body were thighs, chest, and lower legs. The inhalation exposure ratio to the total application amount was significantly low. However, wind seemed to affect the inhalation exposure of operator. For risk assessment, margin of safety was calculated by the application of cloth and dermal penetration rate to obtain values of much larger than 1 in all cases. Therefore, health risk of operators during treatment of acetamiprid in apple orchard could be of least possibility.