This paper was conducted to develop a simulation model of HMT (Hydro mechanical transmission) for a 55 kW agricultural tractor and to verify the model by comparing the measured and simulated data such as the axle torque, rotational speed, and power transmission efficiency. In this study, the HMT model consists of a compound planetary gear, HSU (Hydro-static unit), range shift, spiral bevel gear, and final reduction gear. The compound planetary gear is composed of two planetary gear sets. The HMT has three gear stages, and the maximum tractor speed was selected as 40 km/h. A test bench was installed based on the engine of the HMT platform to evaluate the performance of the HTM, and a simulation model was developed using Romax DESIGNER. A bench test was conducted according to the gear stages to compare the results of the simulation. The similarities between the measured and simulated results were analyzed using the t-test and linear regression analysis. As a result, The range of tractor speed for each gear stage were 1.05-10.22 km/h, 10.74-20.17 km/h, and 20.70-41.40 km/h, respectively. The APE (Absolute percentage error) for tractor maximum speed between target value and simulation results were 2.20%, 0.85%, and 3.50%, respectively. there were no significant differences for the axle torque, rotational speed, and power transmission efficiency. Also, the trend of the power transmission efficiency between the measured and simulated appeared to be similar in all gear stages, and we obtained a simulation model with the accuracy of an R-squared value of more than 0.9. In conclusion, the measured and simulated data were similar to each other. Considering the results of this study, it is considered that this simulation model of the HMT will be useful to develop the HMT tractor and to improve the power transmission efficiency for the optimal design.