InThe movement characteristics of floating green tides are strongly influenced by wind and flow fields, making it challenging to conduct a synchronous comparison analysis. Following an analysis of data from 2015 to 2021 in the Yellow Sea of China, two quasi-synchronous high-precision data pairs from Sentinel-2 MSI and MODIS, with imaging intervals of less than 10 minutes, were identified. These exhibited algae drift deviations of less than one MODIS pixel. In order to examine the authenticity of the 10 m MSI identification results and the detection efficiency of MODIS data , this study employs a simulation in which the Algae-containing Pixel Ratio (APR) is calculated within a coverage area of 25×25 MSI pixels (equivalent to one MODIS pixel) as an aggregation parameter of green tides. The results demonstrated that the majority of green tide patches can be detected by MODIS when the APR in the simulated images is greater than 13%. In contrast, algae with an APR of less than 13%, which are primarily composed of dispersed low-aggregation green tide patches, are difficult to detect and are particularly concentrated around the Jiangsu offshore region. The uncertainty in green tide detection by MODIS data with its coarse spatial resolution is primarily due to differences in its ability to monitor low-aggregation patches. Additionally, fine monitoring of small algae patches using high-resolution images is valuable for the timely detection of the generation, extinction, and convergence of green tide evolution with better accuracy.