This study,Artificial neural network using Anthracnose evaluation of pepper in Chiangmai By the data collected from the National Weather Service in Chiang Mai, a 4-year retrospective including 1096 DataSet. Information is divided in two parts.The first data is 4 years ago of 600 data sets to train artificial neural network. There are input variant information include The maximum-minimum temperature and maximum-minimum relative humidity.There are the remaining number of 496 data sets to test prediction and measuring the efficiency of the prediction by the root mean square error and agreement of index. The study found that the neural network model is very effective, There is quite accurate prediction.In terms of a prediction, there are problems with the pre-process data. Should be added precision, There is increasing the number of data sets to learn of the artificial neural network model. The program will be more effective monitoring