Abstract: In the report， the long-term immersion erosion test on the interface bond durability of BFRP-seawater sea sand concrete was carried out to analyze the long-term degradation law of the interface bond property after real seawater immersion. The soaking time is 30 d， 90 d， 180 d， 270 d， 360 d， 450 d， 540 d， and 630 d， respectively. Based on the drawing test data， the long-term ultimate bond strength retention rate of BFRP bars and seawater sea sand concrete under real Marine environment was simulated and predicted. The results showed that the ultimate bond strength of BFRP bars and seawater sea sand concrete decreases by 66.13% after 630 d of immersion in real seawater， and the degradation rate of 0~270 d is significantly higher than that after 270 d. Bank model and humidity coefficient were used to predict that the retention rates of ultimate bond strength in Marine， outdoor and indoor environments is 31.42%， 57.15%， and 74.85%， respectively.