Abstract: Abstract: Northeast China is a major production area of spring maize. As the slight change of precipitation in spring, the spring drought for maize is frequent. To establish maize spring drought index and quantitative assessment modes based on maize seeding growth, water stress-sowing date field experiments were carried out in the spring of 2010 and 2011 in a maize product area（Yushu city）of the Northeast China. 4 water treatments (no drought, slight, moderate, severe) and 3 sowing date treatments (normal, relatively late and late, each interval for ten days) were designed in the experiment, and soil moisture controlled by the canopy and artificial irrigation. The soil moisture, maize emergence date, emergence rate, leaf age, plant height, biomass in the range of 7th leaf and yield were observed. The spring drought assessment modes were established by analyzing the response of yield to emergence date and seeding growth with regression method. The results showed that the yield of maize was significantly correlated with the emergence date, emergence rate, seeding height, leaf age and seeding biomass. The relationships modes between the relative yield and relative value of the seedling growth factor most as linear functions. Delayed seeding would reduce maize yield, which will be declined by 2.9% when the seeding date was delayed by a day. When emergence rate was decreased by 10%, the yield will be dropped by 9.2%. If the height，leaf age and plant dry quality was reduced by 10%, the yield would drop by 13.4%, 11.1% and 5.5%，respectively. The spring drought cut assessment model which can quantitatively assess or forecast the spring drought impact on the yield by emergence date, emergence rate, leaf age and plant dry quality，and the assessment error was about 6.5%, application test also proved that the effect is batter. The relation modes of relative yield and seedling date delayed days, leaf age difference，emergence rate and seedling dry mass were significant, and the physical and biological meaning of such yield evaluation modes were clear with a high statistical reliability. 2a experimental data fitting test and 3a antual application, the errors are within ±6%. This method is simple and objective which can be applied to the real-time quantitative assessment of drought cut through simple's observation and calculation of spring drought, and provides scientific basis for mitigating disaster and developing the business of the drought insurance.