Abstract: In this paper, the authors aimed at the integration of remote sensing technique and the SIMRIW model to study the effect of cold damage on paddy rice yield per unit area. The Wuchang city of Heilongjiang Province was taken as the study area. The NDVI values were calculated using a series of selected MODIS images from the transplanting to the maturity of rice growth stage so as to retrieve the corresponding LAI values, and furthermore to fit daily LAI values for full rice growth phase. The final results of paddy rice yield per unit area were obtained with the application of SIMRIW parameters. The results showed that the final paddy rice yield per unit area for the year of 2006 was 5411.74 kg/hm² which accounted for 83% of the actual value. Parabola model is the most accurate one out of four statistical models to realize LAI retrieving, and the aggregation fitting is superior to the section fitting in the daily LAI values computation. The study result proved the feasibility of accurate retrieving of the daily LAI from MODIS and provided the reference for the research in the field of the effect of cold damage on paddy rice yield per unit.