The work aims to propose the plan to monitor the VOCs around the printing press on the basis of studying the influence of temperature gradient on the characteristic parameters of VOCs around the printing press, so as to effectively control the VOCs. By establishing the molecular dynamic model of the air flow diffusion process, the characteristics of the gas parameters, such as the diffusion rate and concentration in the boundary conditions were analyzed. The Fluent software was used to simulate such boundary conditions as temperature field and air flow field, and to analyze the simulation of the gas diffusion characteristics of VOCs around the printing press during the offset printing. Combined with the diffusion mechanism of VOCs in printing process and the field operation environment, the VOCs diffusion characteristics were detected and analyzed. The result showed that the temperature gradient had a great influence on the change of such characteristic parameters as VOCs emission rate and concentration, and the theoretical analysis was in agreement with the experimental results. Based on the theoretical research, the method to monitor and control the emission of VOCs in the printing process is proposed, which provides the basis for the management of VOCs in the package printing industry.