To assess the impact of soybean quality during various developmental stages (M7, M9.LODA) changes in day length and temperature of the modeling days to developmental stages in different courses, test using different planting dates in the summer 2009 Field research was conducted Agro meteorology Khorramabad to estimate the number of days to each stage, the number of days from sowing date until the 50% plot phase is considered as the dependent variable and variables, growing degree days (GDD) and photo thermal (PTU) as the independent variable in regression stage were placed on the stage of use Regression appropriate model was selected as the regression coefficients and constant coefficient model of diagnosis and at least 5% probability level is significant and has a maximum ratio of total recognition be. Days from planting to flowering, sowing and planting to pod week to investigate the effect of planting dates accepted. With increasing temperature decreased during the developmental stages of maturity from the influence of increasing day length and agreed it was reduced. Photo thermal variable alone was about 99.5% change and maturity in about 100% of days to flowering and pod changes week finally explained using the software SPSS, 9 for a three-stage model: days to flowering, days Submit to pod and maturity index soybean cultivation, delayed planting and soybean varieties were obtained and given that fixed GDD coefficients were significant in the models were excluded from the model. The purpose of this study models based on temperature and day length to estimate and predict various developmental stages and also to determine the climatic elements impressionable developmental stages for the development of soybean varieties were grown product.