With the rapid explosion of data traffic and dynamic changes in bandwidth，the current fixed grid transmission system architecture is no longer able to meet the requirements. For the next generation high-speed elastic optical network transmission system，the article focuses on two issues：filtering bandwidth and fiber input optical power. The influence of the filter bandwidth on the performance of the next-generation high-speed elastic optical network system is analyzed through simulation transmission. The results show that the filter bandwidth for the next-generation high-speed elastic optical network system should not be greater than 105 GHz. The simulation transmission analysis shows that the influence of the filter bandwidth on the performance of the transmission system is consistent with the actual experiment by building different transmission systems. In order to study the optimal single wave input optical power of the next generation high-speed elastic optical network transmission system without causing significant fiber non-linearity costs，a real-time transmission system is built. The impact of different wavelength input optical power on performance is compared and analyzed through experiments. The results show that +5 dBm is determined as the optimal single wave input optical power for the next generation high-speed elastic optical network system with single carrier transmission rates of 400 Gb/s and 800 Gb/s.