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Background: Government conducts environmental radioactivity surveillance for verification purpose around nuclear facilities based on the Nuclear Safety Law and issues a surveillance report every year. This study aims to evaluate the short and the long-term fluctuation of radionuclides detected above MDC and their origins using concentration ratios between these radionuclides. Materials and Methods: Sample media for verification surveillance are air, rainwater, groundwater, soil, and milk for terrestrial samples, and seawater, marine sediment, fish, and seaweed for marine samples. Gamma-emitting radionuclides including 137Cs, 90Sr, Pu, 3H, and 14C are evaluated in these samples. Results and Discussion: According to the result of the environmental radioactivity verification surveillance in the vicinity of nuclear power facilities in 2017, the anthropogenic radionuclides were not detected in most of the environmental samples except for the detection of a trace level of 137Cs, 90Sr, Pu, and 131I in some samples. Radioactivity concentration ratios between the anthropogenic radionuclides (137Cs/90Sr, 137Cs/239+240Pu, 90Sr/239+240Pu) were similar to those reported in the environmental samples, which were affected by the global fallout of the past nuclear weapon test, and Pu atomic ratios (240Pu/239Pu) in the terrestrial sample and marine sample showed significant differences due to the different input pathway and the Pu source. Radioactive iodine (131I) was detected at the range of < 5.6–190 mBq∙ kg-fresh–1 in the gulfweed and sea trumpet collected from the area of Kori and Wolsong intake and discharge. A high level of 3H was observed in the air (Sangbong: 0.688±0.841 Bq∙m–3) and the precipitation (Meteorology Post: 199±126 Bq∙L–1) samples of the Wolsong nuclear power plant (NPP). 3H concentration in the precipitation and pine needle samples showed typical variation pattern with the distance and the wind direction from the stack due to the gaseous release of 3H in Wolsong NPP. Conclusion: Except for the detection of a trace level of 137Cs, 90Sr, Pu, and 131I in some samples, anthropogenic radionuclides were below MDC in most of the environmental samples. Overall, no unusual radionuclides and abnormal concentration were detected in the 2017’s surveillance result for verification. This research will be available in the assessment of environment around nuclear facilities in the event of radioactive material release.