The work aims to study the production conditions of solventless laminating film used for flexible packaging and analyze the fastness laws by peeling strength, so as to optimize the production process and improve the product quality. By controlling the technological conditions of solventless laminating process, different types of solventless laminating films were prepared separately (dry and light packaging BOPP/CPP combination, boiled packaging PET/PE combination and retorted packaging BOPA/RCPP combination) and the effect of adhesive coating weight and laminating speed on the peeling strength of films was analyzed. Under the experimental conditions, the peeling strength of solventless laminating film samples gradually enhanced as the coating weight increased and met Chinese national standard requirements when the coating weight was 1.0 g/m2, 1.2 g/m2 or 1.6 g/m2. The effect of laminating speed was considerably less noticeable compared to that of the coating weight. The peeling strength at a laminating speed of 450 m/min was only 20% less than that at 100 m/min. Regression analysis on results obtained from tests of heat resistance and high-temperature resistance indicated that heating at high temperature facilitated the curing reaction of adhesive when the coating weight reached 1.19 g/m2 or 1.73 g/m2, resulting in greater peeling strength compared to that before boiling or retorting. In conclusion, with respect to the aforementioned types of laminating flexible packaging, solventless laminating products can meet the Chinese national standards on product strength when coating weight and laminating speed are set within a specific range. Altogether with the lower consumption of energy and less emission of pollutants, solventless laminating becomes a highly viable and much more environmentally friendly substitute for dry laminating process.