In order to rationally protect and utilise natural enemies, we clarified the effects of the ratio of the number of individuals of pests and natural enemies on the indices of the competitive effects of natural enemies (competition coefficient and competition intensity index). In this study, we applied the competition coefficient analysis, grey correlation analysis, competition intensity index analysis and Pearson correlation coefficient method to investigate the effects of the ratio of the number of individuals of Frankliniella intonsa to their main natural enemies on the competitive role index of the main natural enemies in three kinds of tea gardens in 2020 and 2021. According to the data collected from the three tea plantations in two years, the Pearson correlation coefficients of competition coefficient and competition intensity index with the ratio of thrips to natural enemies were -0.7858 and -0.8199, respectively. According to the comprehensive analysis of the data of the three tea plantations in 2020, the Pearson correlation coefficients between the mean competition coefficient and competition intensity index and the ratio of thrips to natural enemies were -0.7391 and -0.7819, respectively. The following relationship between the competitive effect index and the ratio in the three tea gardens in 2021 was not obvious, mainly because the natural enemies other than the nine main natural enemies in the 'Pingyang Tezao’ Tea Garden affected the competitive effect trend. Combining the results of multiple analyses, it was concluded that the competitive action indices of the nine major natural enemies were significantly negatively correlated with the F. intonsa-natural enemy ratios, with the most significant negative correlation being that of the Misumenopstricuspidatu (-0.9936), and the Xysticus ephippiafus was the natural enemy with the highest competitive action indices in the high-ratio group. The results provide a reference for the use of natural enemies in the biological control of F. intonsa.