[Aim]  Accurate quantification of lepidopteran insect eggs is crucial for insect research. However, counting eggs in certain Lepidopteran species can be challenging, necessitating a more convenient method. [Methods]  This study measured and analyzed eggs of varying quantities and weights from Ectropis grisescens and Spodoptera litura. We established a precise linear model describing the relationship between egg numbers and their weights, validating its accuracy, effectiveness, and applicability through experiments. [Results]  Linear regression equations for egg number-weight relationships in W ⁺ and   W^-strains of tea, geometrid, and tobacco cutworm were as follows: Y=0.077 6X-0.264 0 (R²>0.99), Y=0.086 5X-0.087 7 (R²>0.99), and Y=0.053 7X-0.184 5 (R²>0.99), respectively. The relative error in egg predictions using these equations remained under 3%. Experimental validation indicated the method had the highest accuracy for egg counts on days 1 to 4, without significantly affecting hatching rates (P=0.364). Moreover, differences in linear fittings between the different strains allowed for practical strain differentiation. [Conclusion]  This study introduces an innovative method for counting lepidopteran insect eggs and establishes a reliable theoretical and practical foundation for managing and controlling lepidopteran pests.