[Purpose/significance] The purpose of this paper is to research the cumulative rules of PLoS OA articles' views in online media and to enrich the research methods of Altmetrics by mathematical statistics.[Method/process] The tracking data for 38 research papers published in November 2016 by PLoS Biology and PLoS Medicine are collected until October 16, 2017. By using the method of curve fitting and special node calculation, the statistical analysis and test of the recorded data are carried out to explore the cumulative rule of the total page view index.[Result/conclusion] The goodness of fit of logarithmic curve to the cumulative curve of total views is the best, with an average of 0.97. The special point S(x,y) of the cumulative curve is calculated, and the cumulative curve of total views is successfully divided into two stages:centralized view period and decentralized view period, of which the centralized view period accounts for about 10% of all stage, while the view volume exceeds 55% of all stage.