With the intent of decreasing the estimating deviation,the principle and operation guide of an improved software cost estimation model-COCOMOII combined with function point model and multiple regression are introduced.The design and key techniques about implementing the system are also presented.The system uses Brower/Server model and JSP & Java & MySql platform.By fully utiliz- ing the convernience and large information capacity of the network,enough samples for multiple regres- sion can be provided to make the estimated results get access to the reality.