[Objective] The ecological safety of the Yellow River basin was evaluated and the influencing factors were analyzed in order to promote high-quality ecological development of the Yellow River basin and to implement the “Yellow River National Strategy”. [Methods] An ecological safety index system was constructed based on the DPSIR model. The entropy weight-TOPSIS method was used to comprehensively evaluate the ecological safety of the provinces along the Yellow River basin from 2011 to 2020. The BP-DEMATEL model was used to analyze the key factors of ecological safety. [Results] ① The overall level of ecological safety in the Yellow River basin was low, but showed a slow upward trend. The average ecological safety index was no more than 0.4 in the past 10 years, but has gradually increased from 0.322 in 2011 to 0.365 in 2020. ② The ecological safety of each province showed three evolutionary trends of rising, fluctuating, and declining. The average ecological safety indexes, from high to low, were: Shandong (0.431), Sichuan (0.372), Inner Mongolia (0.371), He’nan (0.362), Shanxi (0.349), Ningxia (0.343), Shaanxi (0.326), Gansu (0.302), Qinghai (0.301). ③ The BP-DEMATEL results showed that the key factors of the provinces with upward trends of ecological safety were scattered outside the pressure index layer. The key factors of the provinces with fluctuating and declining trends were concentrated in the impact and pressure index layers, respectively. [Conclusion] The ecological safety of the Yellow River basin as a whole showed a benign evolution trend, but regional development was unbalanced. Provinces should implement regulation and control around key factors.