Abstract: To realize the lotus root standardization production,and make intelligent decision against disease and insect pest quickly,we develop five databases firstly including lotus root base knowledge,cultivars information,cultivation techniques,common diseases,lotus root insect pests.With lotus root eco-physiology knowledge and expert experiences,some models were developed in intelligent selecting cultivars and disease diagnosis.Based on these databases and models,A Web-based decision system was developed with Asp.Net for lotus root intelligence selecting cultivars and diagnosis.This system realizes remote information query and online learning by video,intelligent selecting lotus cultivars according the farmland environment and production purpose,give diagnosis for common disease,and make the decision against the common disease and insect pest online.