Abstract: In order to study the improvement and change law of main agronomic traits and yield of the main soybean cultivars for more than 60 years in SanJiang plain, and to guide current and future variety improvement and innovation, we conducted a field plot experiment with eighteen main cultivars of different years with the same maturity in SanJiang plain as test materials. The results showed that the main agronomic traits had changed along with the advance of the years. The plant height and effective branches number showed a reducing trend. The bottom pod height had hardly changed and showed an increased overall trend. The main stem node number showed an increased trend. The lodging resistance ability showed an enhanced trend. The number of growth days increased year by year. The pod number per plant, seeds number per pod, seeds number per plant and seed weight per plant showed an increasing trend. The 100-seeds weight increased in a fluctuant trend. The yield showed an increased trend year by year. The rangeability of the yield was from 2509.20 kg/hm2 to 3311.25 kg/hm2. The annual mean yield increase was 13.35 kg/hm2, and the growth rate was 0.53%. The improvement and change of the main agronomic traits, especially the extension of the mature period and the improvement of the yield, led to the continuous replacement and change of the main soybean cultivars. The results could provide important guidance and reference for current and future variety improvement and innovation.