In early 2020, the world was shocked by the spread of new type of coronavirus (Sars-Cov-2), which caused respiratory illness called Covid-19. WHO set that Covid-19 is a global pandemic on 11th of March 2020. In Indonesia, first positive case of Covid-19 confirmed by the President, Joko Widodo, on 2nd of March 2020. Until 18th of May 2020, Indonesia had reported 18.010 positive case of Covid-19 with the number of deaths reached 12.495 peoples. In order to increase the effectivity and efficientcy of handling the Covid-19 pandemic in Indonesia, it takes a forecasting model that can predict the number of positive cases weekly accurately. To get an accurate forecasting model, it requires sufficient data fitting. The purposes of this  research is to identifying which countries that had similar positive case data trend with Indonesia using Tangent Control Chart (t-chart). Tangent value can be obtained from the curve of these positive case data trend that can be used as a variable which can be monitored using a control chart. So, the t-chart hopefully can be a new innovation to detect a small shift from a set of historical data if reviewed from the data trend. The result of analysis using Individual Moving Range Chart (I-MR Chart) and t-chart to 183 countries that affected by Covid-19 pandemic, there are 71 countries that have a positive case data trend similarity with Indonesia. Positive cases data set from 72 countries including Indonesia can be used as a data set to perform forecasting model data fitting for predicting positive cases of Covid-19. The result of this research can be conveyed to the government to make policy about Covid-19 pandemic, also for indonesian citizens to increase awareness of the Covid-19 pandemic.