This study focused on plankton community composition and some physicochemical parameters to the changes of buffer zone from four sampling sites at the North and Eastern side of Lake Tana to investigate the buffer zone degradation and its impact on plankton composition and biomass. The studies were carried out for six month from December 2020 to May 2021. The four sampling sites were selected based on the anthropogenic impact on the buffer zone. Human Disturbance Assessment (HDA), Remote Sensing (RS), and geographic information system (GIS) were used to explore the buffer zone characteristics. Major in-situ physicochemical measurement and a composite sample of fetched water for Planktons and nutrient analysis were done monthly from the separate sampling sites. A total of 120 composite samples were analyzed during the study period. The SPSS software was used to perform ANOVA, regeration, and correlation analysis between variables. MS Excel 2007 was used to determine the Shannon diversity index (SDI). The results detected that, percentages of human disturbance were shown severity, moderate, low and minimum at the purposive selected sampling sits. Water transparency ranged from 13.3 to 72 cm, turbidity(NTU),19 to 98, pH, 6.42 to 8.6, TDS, 86 to 142.3 mg/L, conductivity, 121.1 to 256.5 µS/cm, total nitrogen(TN), 1.64 to 4.864 mg/L, total phosphorus, 0 to 0.39 mg/L and chlorophyll-a, 1.22 to 9.10 µg/L. All of these were significantly different spatially at the sampling sites, and dissolved oxygen was positively correlated with depth, Secchi-depth, pH, and Chl-a. Mean Chl-a concentration at pelagic water (2.64µg/L) was higher than the other two sites (Seraba, 2.34µg/L, and kirrigna, 2.48µg/L) having degraded (no) buffer zone. Hence, the pelagic site was more productive than the non-buffer sampling sites. Fifty-three phytoplankton species classified into four divisions, Chlorophyta 47%, Bacillariophyta 30%, Cyanophyta 19%, and Euglenophyta 4% were found. Ten major zooplankton species made up of four rotifers, three cladocerans, and three copepods species and their developing stages were recorded. Large variations in diversity and productivity of the planktonic communities were observed in Debresina and Seraba study sites. The number of zooplankton species was not different among the four sampling stations. The variation of the status of a buffer zone in the study side of Lake Tana contributes to the variations of physicochemical parameters, community composition of plankton and Biomass. Avoiding any man-made activities and applying buffer zone on the lake shore were some of the recommendations. Key words: Composition, Man-made activities, Lake buffer zone, Plankton, Productive