With the rapid growth of Internet and websites

especially the emergence of mobile internet

PaaS system has emerged and developed rapidly to deal the demands that rapid deployment

automatic maintenance of web applications. At the same time

the data monitoring problem of PaaS system began. The purpose of this paper is to solve this problem. This paper defines what data to monitor and where to get the data.The PaaS data monitoring system is design on three levels: collection of monitoring data

analysis of collection data and display of analysis result. This system can deal with the heterogeneity of monitoring data effectively.