Abstract: The thickness of plastic film is one of the main factors affecting the recycling of waste plastic film. In order to comprehensively grasp the current situation and changing trends of the thickness of plastic film already covered in farmland, explore the problems in the use of plastic film, and establish a long-term mechanism for the recycling and utilization of waste plastic film in Liaoning Province. The small-scale film-covered plots in Liaoning Province were taken as the research object, and the main film-covered areas and different film-covered crops were selected for three consecutive years from 2021 to 2023 to monitor the actual situation of film thickness. The results showed that there were differences in the thickness of covered plastic film in different regions. The use of mulch with a nominal thickness of less than 0.010 mm was mainly prominent in Chaoyang, Jinzhou and Anshan, accounting for 61.4%, 50.0% and 44.4% respectively.The nominal thickness of mulching film in different years showed an increasing trend year by year, and the proportion of mulching film with a nominal thickness of ≥0.010 mm was 69.3%, 70.9% and 76.9% respectively. By monitoring the actual situation of the thickness of plastic film in the field, the problems in the use of plastic film in Liaoning Province were analyzed. It was suggested that the relevant functional departments should earnestly implement the supervision responsibilities, strengthen the supervision of the key links of plastic film production and sales, and do a good job in source control and process supervision. All localities should combine the types and characteristics of film-covered crops, adjust measures to local conditions, and implement classified policies. At the same time, we will fully integrate the national film science use recycling pilot project, increase the financial support for thickening high-strength film and fully biodegradable film, and enhance the enthusiasm of farmers for scientific film use.