Cloud computing is becoming a well-known buzzword nowadays. Many companies, such as Amazon, Google, Microsoft and so on, accelerate their paces in developing Cloud computing systems and enhancing their services to cater for a wide variety of users. However, there is no study that focuses on search engine for Cloud computing system. Hence, this paper presents search engine for Cloud computing system (Cloudle). To semantically define the relationship among Cloud services, Cloud ontologies (CO-1 and CO-2) are designed. CO-2 contains a set of Cloud concepts, individuals of those concepts, and the relationship among those individuals while CO-1 contains only concepts. It is used for determining the similarity among Cloud services with three kinds of reasoning methods (1) concept similarity reasoning, (2) object property similarity reasoning, and (3) datatype property similarity reasoning. The architecture of Cloudle is also briefly presented. Finally, empirical results show that the result of using Cloudle with CO-2 has significantly better performance in finding the appropriate Cloud service than the result using Cloudle with CO-1, the result without the Cloud ontology, and the result without Cloudle.