主要介绍了干旱监测遥感支持系统的设计和实现,说明了系统的整体框架结构及其所具备的通用性、可扩展性等特点。为了实现系统的可扩展性,根据COM原理,遥感支持系统开发了一个特别接口,用户可以借此向系统中添加自己开发的其他功能模块,或新的文件格式驱动。此外还着重介绍了垂直干旱指数的计算原理和程序实现算法,并结合宁夏试验区的实际应用对监测结果进行了展示。文中重点介绍了利用C＋＋语言实现垂直干旱指数（PDI）的详细步骤,并对其中寻找土壤点和内存管理等关键算法进行了细致分析。

The main objective of this paper is to introduce the implementation of Perpendicular Drought Index(PDI),a simple,effective drought monitoring tool,in integrated remote sensing supporting system(IRSSS) for parameter retrieval and drought estimation.The quantitative remote sensing models are changing and various and the remote sensing data formats are complex and diverse.The research group used component oriented programming thoughts to solve these problems,making this system extendable in data source and models.The system could deal with various familiar formats of RS image.According to the COM rule,the IRSSS developed a particular interface in order to guarantee the users add new function module or file I/O driver by themselves.This paper introduces the implementation of PDI using C program language.There are four steps designed to complete the task.The general process and purpose of every step is explained and especially the method of finding soil point and memory management are introduced as the key technology.Our research group has implemented the drought-monitoring function based on the basis of the IRSSS system.Furthermore,according to the observation data of Ningxia the research group generated many results of various Drought Indices.The paper also presents the results of evaluated drought situation of Ningxia Huizu Autonomous Region of China that indicates the accordance with regional hydro-environmental data.