This study investigates the effect of WeChat official accounts on constructing the academic impact of scientific journals. It focuses on the journals selected by the Excellence Action Plan for China’s STM Journals (hereafter referred to as the Excellence Action Plan of China) and those selected by the Excellence Action Plan for STM Journals in Shaanxi province, China (hereafter referred to as Sanqin Plan). This paper employs Pearson’s coefficient to quantitatively assess the effectiveness of creating WeChat official accounts and the WeChat Communication Index (WCI) in enhancing impact indicators and online communication metrics, as well as the effectiveness of the WeChat platform in disseminating academic articles. Statistical analysis reveals that 91.43% of the journals in the Excellence Action Plan of China, along with all journals in Sanqin Plan, have established WeChat official accounts, with the peak years of establishment occurring in 2015 and 2016. The establishment of WeChat official accounts can improve impact indicators and online communication metrics. For the journals in the Excellence Action Plan of China, growth ratios for impact metrics are primarily concentrated in the ranges of 0–60 and above 100, while their growth ratios for online communication metrics are predominantly in the 0–60 range. The monthly average WCI (V14.2) values for the journals in the Excellence Action Plan of China and in the Sanqin Plan are in the ranges from 370.21—437.84 and 261.33—278.55, respectively, with 56.20% and 87.5% of values falling below 400, indicating that the impact of most WeChat official accounts of these journals is relatively small, and adjustments in construction and operation are needed. Significant difference in average WCIs is observed across different disciplines. For journals in the Excellence Action Plan of China, those in the transportation and aerospace disciplines have higher WCI values, while for journals in the Sanqin Plan, those in the transportation discipline show the highest WCI value. For the journals in the Excellence Action Plan of China, the WCI values of 400 or above have a moderate positive correlation with impact indicators, while those below 400 exhibit only a weak positive correlation. For the journals in Sanqin Plan, the WCI values below 400 have a weak positive correlation with impact indicators. The communication of academic articles through journal WeChat official accounts can enhance both impact indicators and online communication metrics, and the larger the WCI value, the better the communication effect. Successfully planning and operating the WeChat official account can attract more audiences. A comparison of “reading times” and “download times” for the same academic content on mobile and PC platforms reveals that users prefer to quickly browse academic articles on mobile devices and read them in depth on PCs. Mobile browsing volume is in weak positive correlation with downloads and citation counts, while PC browsing volume is in weak positive correlated with citation counts, and PC download volume has a moderate positive correlation with citation counts. This indicates that simply transferring the same content of academic articles published in databases to WeChat official accounts does not significantly increase citation counts. Based on these findings, two different operational strategies are proposed. The first is an enhancement strategy, aiming to increase the innovation and service orientation of WeChat official accounts by diversifying content. The second strategy involves constructing a matrix of official accounts, combining content across different professional fields of journals, positioning the content and push methods of different official accounts, establishing a more systematic structure of communication content for these accounts. The results of this study provide valuable insights for the scientific journals in setting operational goals for WeChat official accounts, thus enhancing the academic impact of these scientific journals.